education

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RKMFILES CENTER FOR
COMPREHENSIVE STUDIES
Room 309, 3rd
Floor A-Building, Main AUF Campus, Angeles University Foundation
Email: rkmfiles@yahoo.com Website: www.rkmfiles.net CP: 09088849680
COMPILED BY:
LUCIA M. HIPOLITO -- ROMMEL K. MANWONG -- ALFIE P. SARMIENTO
REVIEW NOTES IN
CRIMINAL IDENTIFICATION &
DETECTION
FUNDAMENTALS OF CRIMINAL INVESTIGATION
SPECIAL CRIME INVESTIGATION
FIRE TECHNOLOGY & ARSON INVESTIGATION
TRAFFIC MANAGEMENT & ACCIDENT
INVESTIGATION
DRUG EDUCATION & VICE CONTROL
(NARCOTICS INVESTIGATION)
POLICE REPORT WRITING
(TECHNICAL/INVESTIGATIVE WRITING)

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FUNDAMENTALS OF CRIMINAL INVESTIGATION
BASIC CONCEPTS
Criminal Investigation- is an art that deals with the identity and location of the offender and prove his guilt in a
criminal proceeding.
Criminal Investigation- it is the systematic method of inquiry that is more a science than an art. The logic of scientific
method must however, be supplemented by the investigator's initiative and resourcefulness. The sequences of the
investigation should be regarded by scientific, operating framework that requires improvising on the part of the
investigator.
Criminal Investigation is an Art –based on intuition, felicity of inspiration or by chance; and a Science –based on
adequate professional preparation and abundance of certain qualities
Investigator- is the person who is charged with the duty of carrying out the objectives of criminal investigation. He is
an individual who gathers documents and evaluates facts about crime
Special Crime Investigation- deals with the study of major crimes based on the application of special investigative
techniques. It is also the study concentrates more on physical evidence; it’s collection, handling, identification and
preservation in coordination with the various criminalists in the crime laboratory. Special crime investigation involves
close relationship between the investigator in the field and the investigator in the laboratory- the Criminalist.
Duty of Criminal Investigator
1. Establish that, in fact, a crime was committed under the law.
2. Identify and apprehend the suspect.
3. To recover stolen property.
4. To assist the state in prosecuting the party charged with the offense.
Job of the Criminal Investigator
1. Discover whether or not an offense has been committed under the law.
2. After determining what specific offense has been committed, he must discover how, when, where, why, what
offense was committed.
Methods of Identifications of Criminals
Criminal are identified thru the following:
1. Confession and Admission
2. Statement of witnesses
3. Circumstantial Evidence
4. Associative Evidence
A. Confession- this is an expressed acknowledgement by the accused in criminal cases of the truth of his guilt as to
the crime charged or of some of the essential part there of. There is no implied confession for it is positive and direct
acknowledgement of guilt. It is the best means of identifying criminal.
Rules in Confession
a. Confession need not to be in writing
b. Confession may be written in a language which the accused does not speak

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c. Confession must be freely and voluntarily made
Voluntarily –means that the accused speak of his free will and accord, without inducement of any kind and with the full
and complete knowledge of the nature and consequences of the confession.
Freely- when the speaking is so free from the influence affecting the will of the accused at the same time the
confession was made.
Requirement for confession as proof of guilt
1. Other corroborative evidence must support it.
2. Corpus delicti- must be established separately (the actual commission of the crime charged. It refers to a
particular crime and signifies that specific offense had been actually committed by someone being composed of
two elements: that certain results were produced, that someone is criminally responsible
3. Confession must be made voluntarily.
B. By EYE-WITNESS TESTIMONY- description made by eyewitness
Value of identification by eyewitness testimony depends on the following: (credibility-bringing honor)
1. the ability of the eyewitness testimony to observe and remember the relative “distinctiveness” of the accused
appearance
2. The prevailing conditions, visibility and observation
3. The lapse of time between the criminal event and identification
Methods of Identification made by eyewitness
1. Verbal Description- portrait parley vividly describing in words the appearance of a person by comparing and thru
personal appearance.
2. Photographic files (rogues gallery)
3. General photograph- files of photograph in any given establishment.
4. Artist Assistance or composite sketches- drawing or sketching the description of a person’s face by the
cartographer
5. Police line-up- selecting the suspect from a group of innocent persons to eliminate the power of suggestions as
factor of identification
Cartography- the art of sketching the image of a person or the art of making map
Bases of the eyewitness in the identification of criminal
1. Face-forehead, eyebrow, mustache, eyes, ears, cheeks, mouth, lips, teeth, chin, jaw, etc.
2. Neck- shape, length, Adam’s apple
3. Shoulder- width and shape
4. Waist- size, shape of the abdomen
5. Hands- length, size, hair, condition of the palms
6. Fingers- length, thickness, stains, shape of nails and condition
7. Any deformities (cross eyed, limping and etc.)
8. Teeth-
9. Gait
Bases of Physical Description of Physical Appearance
1. Mug Shot
2. Artist Drawing
3. Composite Sketches

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4. Verbal description or Portrait Parley
HISTORICAL FEATURES IN CRIMINAL INVESTIGATION
The art and science of Criminal Investigation that exist today is the result of countless development since
policing was conceived and then institutionalized. The following is just a brief account of some of the major milestone in
the history of Criminal Investigation.
WORLDWIDE DEVELOPMENT
1720s, ENGLAND: - JONATHAN WILD He was a buckle maker then a brothel operator; a master criminal who
became London’s most effective criminal investigator. He was the most famous THIEF-CATCHER in 1720s. His
methods or techniques made popular the logic of EMPLOYING A THIEF TO CATCH A THIEF. He conceived the idea
of charging a fee for locating and returning stolen property to its rightful owners.
1750s, ENGLAND: - HENRY FIELDING An Englishman who wrote a novel entitled “Tom Jones” and was appointed as
magistrate (sheriff) for the areas of Westminster and Middle Age, London. He was the creator of the BOW STREET
RUNNERS while he was the magistrate; he formed a group of police officers attached to the Bow Street Court, and not
in uniform, performing criminal investigative functions.
1753, ENGLAND: - SIR JOHN FIELDING The younger brother of Henry Fielding who took over the control of Bow
Street Court in 1753. His investigators were then called Bow Street Runners and became quite effective because of his
personal guidance despite the fact that he was blind. He introduced the practice of developing paid informants, printing
wanted notices, employing criminal raids, and bearing firearms and handcuffs.
1759, USA: The US CONGRESS created the office of the GENERAL AND REVENUE CUTTER SERVICE. This is the
first organized federal law enforcement and investigative effort made by the US government.
1800, LONDON: - PATRICK COLQUHOUN A prominent London president who proposed the unique idea of creating
sizeable uniformed force to police the city of London in order to remedy the public outcry concerning the alarming
increase of criminality during the early 1800s. His proposal was considered too radical and was dismissed by the Royal
Court.
1811, FRANCE: - EUGENE ‘Francois” VIDOCQ He was a criminal who turned Paris Investigator. He is a former
convict who became a notorious thief-catcher in France. He is credited as the founder of LA SURETE, France’s
national detective organization. He made popular the concept of “SET A THIEF TO CATCH A THIEF”. He introduced
the concept of ‘TRADE PROTECTION SOCIETY’, which is a forerunner of our present-day credit card system. For a
fee, any owner of a shop or business establishment could obtain particulars concerning the financial solvency of new
customers. He created a squad of ex-convicts to aid the Paris police in crime investigation.
1829, LONDON: - SIR ROBERT PEELS The founder and chief organizer of the London Metropolitan Police –the
SCOTLAND YARD. He reiterated the idea of creating sizeable police force in his recommendations, which lead to the
passage of the Metropolitan Police Act. This act had a tremendous impact on the history of criminal justice in general,
and on the development of criminal investigation specifically. He introduced the techniques of detecting crimes such
as: detectives concealing themselves, and secretly photographing and recording conversations.
1833, ENGLAND: The Scotland Yard employed the first undercover officer while in
USA: First daytime paid police department was established in Philadelphia, USA.
1835, USA: TEXAS RANGERS was organized as the first law enforcement agency with statewide investigative
authority, the forerunner of the Federal Bureau of Investigation.
1839: - The birth year of Photography. WILLIAM HENRY FOX TALBOT explained a photographic process he had
invented to the Royal Society of London.

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JACQUES MANDE DAGUERRE gave a public demonstration in Paris of his discovery - a photographic
process he developed in collaboration with NICEPHORE NIEPCE.
1842: Scotland Yard created the first FULL-TIME INVESTIGATIVE, which is a forerunner to the Criminal Investigation
Division of Scotland Yard.
1851, BOSTON, MASSACHUSETTS, USA: Multi-suspect ID LINE-UP is employed in the first time.
1852, USA: - CHARLES DICKENS - Through his story entitled BLEAK HOUSE, he introduced the term DETECTIVE
to the English language.
1852, USA: - ALLAN PINKERTON - America’s most famous private investigator and founder of Criminal Investigation
in USA. He established the practice of handwriting examination in American courts and promoted a plan to centralize
criminal identification records.
1856, USA: - KATE WAYNE: The first woman detective in the history of criminal investigation, hired by the Pinkerton
Agency.
1859, USA: Appellate courts recognized/accepted photographs as admissible evidences when they are relevant and
properly verified.
1865, USA: US SECRET SERVICE was founded to investigate counterfeiting activity in post-civil war America.
1866, USA: - INSPECTOR THOMAS BYRNES: A New York Chief of Detectives introduced the MODUS OPERANDI
FILE.
1866, Liberty, Missouri, USA: The JESSE JAMES GANG made the first bank hold-up which mark the beginning of
the gang’s 15-year hold-up and robbery spree (12 bank hold-ups and 12 train stage coach robberies in 11 states). Clay
County Savings Association was their first victim and their take was $ 60,000.00.
1877, ENGLAND: - HOWARD VINCENT: Headed the newly organized CRIMINAL INVESTIGATION DEPARTMENT
in Scotland Yard.
1882, FRANCE: - ALPHONSE BERTILLON: A French Police Clerk who introduced and established the first
systematic identification system based on ANTHROPOMETRICAL SIGNALMENT (or Anthropometry) he is considered
as the FOUNDER OF CRIMINAL IDENTIFICATION.
1884, CHICAGO, USA: The Chicago Police Department established the first American Criminal Identification Bureau.
1887, DR. ARTHUR CONAN LYLE: He popularized the Scientific Criminal Investigation by creating the fictional
detective SHERLOCK HOLMES and his friend Dr. WATSON. Holmes was featured in 6 short stories and 4 novels.
1892, ENGLAND: - FRANCIS GALTON: An Englishman who published his study on classifying fingerprints. While
other scientists were studying fingerprints in their biological nature, Galton recognized their uniqueness and
potentiality/significance in criminal identification.
1893, GERMANY: - HANS GROSS: An Englishman who published a handbook for Examining Magistrates in Munich,
Germany and advocated the use of scientific methods in criminal investigation process.
1948, ABERDEEN, SCOTLAND: A new concept was introduced in the field of criminal investigation. This is known as
TEAM POLICING. In team policing, there is no patrol division or criminal investigation per se. In this system, a team of
police officers is assigned to patrol and investigate all criminal matters within their area of jurisdiction or district. Team
policing required that police officers who respond to a call regarding a criminal case should investigate the case to its
conclusion.
1954,USA: - Dr. PAUL KIRK: Best known American criminalist who headed the Department of Criminalistics as the
University of California, USA.

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1961,USA: - Mapp vs. Ohio (376 vs. 584): The Supreme Court ruled the illegally obtained evidence is inadmissible in
state criminal prosecutions.
1965, USA: Office of Law Enforcement Assistance (forerunner of the Law Enforcement Assistance Administration –
LEAA) was established to fund and coordinate administration, research and training in criminal justice.
1966, USA: - MIRANDA vs. ARIZONA (384 vs. 436): The US Supreme Court established procedural guidelines for
taking criminal confessions.
DEVELOPMENT IN THE PHILIPPINE SETTING
1712. CARABINEROS DE SEGURIDAD PUBLICO: Organized for the purpose of carrying out the policies or
regulations of the Spanish government. The members were armed and considered as the mounted police. Later, they
discharge the duties of a part, harbor, and a river police.
1836. GUARDRILLEROS: A body of rural police organized in each town, which was established by the Royal Decree
of January 8, 1836. This police force was composed of 5% of the able-bodied inhabitants in each town or province, and
each member will serve for at least 3 years.
1852. GUARDIA CIVIL: An organization created by the Royal Decree issued by the Spanish Crown Government on
February 12, 1852. It relieved the Spanish Peninsular Troops of their works in policing towns. It consisted of a body of
Filipino policemen organized originally in each of the provincial capitals of the Central provinces of Luzon under the
command of Alcalde (Governor).
NOV. 30, 1980. INSULAR POLICE FORCE: Established during the Filipino-American War (1898-1901) upon the
recommendation of the American Commission to the Secretary of War.
JULY 18, 1901. ACT # 175: The act establishing the Insular Police Force which was titled as “AN ACT PROVIDING
FOR THE ORGANIZATION AND GOVERNMENT OF AN INSULAR CONSTABULARY”. The organic act creating the
Philippine Constabulary.
OCT. 3, 1901. ACT # 255: The law which established the Philippine Constabulary
REVISED ADMINISTRATIVE CODE OF 1917, Section 825: The law stated that the Philippine Constabulary is a
national Police Institution for preserving the peace, keeping the order and enforcing the law.
SEPT. 8, 1966. RA # 4864. (Law co-authored by Rep. Teudolo Natividad): The law otherwise known as the
POLICE ACT OF 1966, It created the Office of the Police Commission which was later called National Police
Commission (NAPOLCOM). In its inception, the Police Commission was under the Office of the President. It was
created as the supervisory agency to oversee the training and professionalization of the local police forces. Through
this law, reformation and professionalization of the police service gained official recognition.
AUG. 8, 1975. PD#765: The law which stipulated that the office of the NAPOLCOM was under the office of the Ministry
of the National Defense. It defined also the relationship between the Integrated National Police and the Philippine
Constabulary. This is in compliance with the provisions of Section 12, Article 15 of the 1973 Philippine Constitution.
1935 PHILIPPINE CONTITUTION, Article III, Section 17 (1) - The law provides that:” In all criminal prosecutors, the
accused shall…
. Enjoy the right to be heard by himself and counsel…
…
”. Criminal prosecution was however interpreted by
the court in US vs. Beechman (25 Phil 25,1972) to mean the proceeding at the trial court from arraignment to rendition
of judgment.
1973 PHILIPPINE CONSTITUTION, Article III, Section 20
“No person shall be compelled to be a witness against himself. Any person under investigation for the
commission of an offense shall have the right to remain silent and to counsel, and to be informed of such right. No

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force, violence, threat, intimidation nor any means, which vitiate the free will, shall be used against him. Any confession
obtained in the violation of this section shall be inadmissible as evidence.
The warning of the right to remain silent must be accompanied by the explanation that anything said can and
will be used against the individual in court. This warning is needed in order to make him aware not only of the privilege,
but also of the consequences of forgetting it. (People vs. Duero, 104 SCRA 379, 1981)
1983 –MORALES vs. JUAN PONCE ENRILE (GR#61016-17; April 26,1983; SCRA 538)
The ruling in this case makes it clear that the MIRANDA WARNING as it is generally called have to be made
so that a confession can be admitted. Therefore, while upon police custody for investigation, the accused must be
appraised of his:
1. Right to remain silent with explanation that anything that he might say maybe used against him in
the court of the law;
2. Right to talk to a lawyer, a relative, or a friend, and have a lawyer ready and a friend present while
he is being questioned; and
3. Right to the appointment of a lawyer if he cannot afford one.
1985 –PEOPLE vs. GALIT (GR#51770;March 20,1985) - The right to a counsel maybe waived but the waiver, to be
valid, must be made with assistance of a counsel.
1987 PHILIPPINE CONSTITUTION, Article III, Section 12 (1) - “Any person under investigation for the commission of
an offense shall have the right to be informed of his right to remain silent and to have a competent and independent
counsel preferably of his own choice. If the person cannot afford the services of a counsel, he must be provided with
one. These rights cannot be waived except in writing and in the presence of a counsel.
Article XVI, Section 5(4) - “No member of the armed forces in the active services shall, at any time, be appointed for
designated in any capacity to a civilian position in the Government including government owned or controlled
corporation, or any of their subsidiaries.”
Article XVI, Section 6 - “The State establish and maintain one police force, which shall be national in scope and
civilian in character, to be administered and controlled by a National Police Commission. The authority of local
executives over the police units in their jurisdiction shall be provided by law.”
1990, RA 6975 - DILG ACT, Philippine National Police (PNP) together with BFP and BJMP organization
1998, RA 8551 –PNP Reform and Reorganization Act

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GENERAL PRINCIPLES OF CRIMINAL INVESTIGATION
In the performance of his duties, the investigator must seek to establish the six (6) cardinal points of
investigation, namely: what specific offense has been committed; how the offense was committed; who committed
it; where the offense was committed; when it was committed; and why it was committed.
The Phases of Criminal Investigation
a) Preliminary Investigation - identify the criminal through confession; eyewitness testimony; circumstantial
evidence; and associate evidence
b) Follow Up Investigation - trace and locate the criminal; and
c) Final Investigation - proved by evidence the guilt of the suspect/s.
In proving the guilt of the accused in court, the fact of the existence of the crime must be established; the
defendant must be identified and associated with the crime scene; competent and credible witnesses must be
available; and the physical evidence must be appropriately identified. The proof of guilt will depend on the
establishment of the essential elements of the crime. The investigator must know by heart the elements of a
specific crime.
Tools of an Investigator in Gathering Facts
a) Information – Data gathered by an investigator from other persons including the victim himself and from
Public records; Private records; and Modus Operandi file.
b) Interrogation and Interview –Questioning of witnesses, suspects, and offended parties.
c) Instrumentation – Scientific examination of real evidence, application of instrument and methods of the
physical sciences in detecting crime.
INFORMATION
All evaluated materials of every description including those derived fro observation, reports, rumors, imagery,
and other sources from which intelligence in produced.
Information is a communicated knowledge by others obtaining by personal study, investigation, research,
analysis, observation. The use of modern gadgets in intelligence and other things and material that possess or contain
a desire information or knowledge.
Two General classifications of sources of information:
1. Open Sources –99% of the info collected are coming from open sources.
2. Close Sources –1% of info from close sources.
Overt Intelligence –is the gathering of information or documents procured openly without regard as to whether the
subject or target become knowledgeable of the purpose
Open Sources: Includes information taken from
 Enemy activity –POW –Civilians - Captured documents
 Map - Weather, forecast, studies, report - Agencies
Covert Intelligence –is the secret procurement of information, which is obtained without the knowledge of the person
or persons safeguarding vital intelligence interest.
Close Sources: are information usually taken through:
 Surveillance
 Casing
 Elicitation

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 Surreptitious entry
 Employment of technical means (Bugging and Tapping device)
 Tactical Interrogation
 Observation and Description
Other sources of Information: Overt and Covert
 Routine patrol and Criminal investigation
 Use of informants and Interrogations
 Search and seizures and Cordon and scratch
 Checkpoints and Police public relations activities
 Coordination with law enforcement agencies
 Inmates of various city jails, national penitentiary, military stockade.
 Statistics
Persons as sources of Information
Informant Net –It is a controlled group of people who worked through the direction of the agent handler. The
informants, principal or cutouts supply the agent handler directly or indirectly with Intel information
Informants (Asset) –people selected as sources of information, which could be voluntary, or in
consideration of a price.
 Informant –refers to a person who gives information to the police voluntarily or involuntarily with out any
consideration
 Informer –those who give information to the police for price or reward
Types of Informants
1. Criminal Informant –an informant who give information to the police pertaining to the underworld about
organized criminals with the understanding that his identity will be protected
2. Confidential Informant –is similar to the former but he gives information violate of the law to includes
crimes and criminals
3. Voluntary Informant –a type of informant who give information freely and willfully as a witness to a
certain act
4. Special Informant –those who gives information concerning specialized cases only and it is regarded a
special treatment by the operatives (ex. teachers, businessmen)
5. Anonymous Informant – those who gives information through telephone with the hope that the
informant can not be identified
Sub-type of Informant
1. Incidental Informant – a person who casually imparts information to an officer with no intention of
providing subsequent information
2. Recruited Informant –A person who is selected cultivated and developed into a continuous source of
info
Categories of Recruited Informants:
1. Spontaneous or Automatic Informant – Informants who by the nature of their work or position in
society have a certain legal, moral or ethical responsibilities to report info to the police
2. Ordinary run of he Mill Informants –Informants that are under the compulsion to report info to the
police
3. Special Employee –informants who are of a specific operational nature
Other classification of Informant
Automatic – Penetration - Full time - Rival – Elimination - False Informant - Frightened Informant - Self-
aggrandizing Informant - Mercenary Informant - Double Crosser Informant - Woman Informant - Legitimate
Informant

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Common Motives of Informants
Reward –Revenge - Fear and avoidance of punishment –Friendship - Patriotism –Vanity - Civic-Mindedness –
Repentance –
Competition -Other motives
INFROMANT RECRUITMENT
Phases
1. Selection –it is particularly desirable to be able to identity and recruit an informant who has access to many
criminal in-group or subversive organization. Wide access is probably the single most important feature in the
consideration of recruiting the potential informant
2. Investigation –the investigation of the potential informants that has tentatively identified as a “probable” must
be as thorough as possible. It must establish possible existing motives as to this person might assist the
police Intel community. Failure to do so will deny this office who must perform the approach and persuasion
phase with little more that a guess. If necessary, conduct complete background investigation (CBI)
3. Approach –approach must be done in a setting from which might include pleasant surroundings, perhaps a
confidential apartment, completely free form any probability of compromise, preferably in an adjacent city or
a remote area foreign to the informants living pattern.
4. Testing –the testing program should begin, of course, with the limited assignment, with a gradual integration
into the more important areas. The occasional testing of an informant should continue through the entire
affiliation
INTERVIEW AND INTERROGATION
1. Interview Defined. - An interview is the questioning of a person believed to possess knowledge that is in official
interest to the investigator.
2. Importance of Interview. - Interview in crime investigation is very important considering that the person
interviewed usually gives his account of an incident under investigation or offers information concerning a person
being investigated in his own manner and words.
Basic Assumptions: Nobody has to talk to law enforcers. No law compels a person to talk to the police if he
does not want to. Therefore, people will have to be persuaded, always within legal and ethical limits, to talk to law
enforcers. This makes interviewing an art:
3. The Person Interviewed
Consider:
a) His ability to observe.
b) His ability to remember
c) His ability to narrate.
d) His mental weakness because of stupidity or infancy
e) His moral weakness because of drunkeness, drug addiction, his being a pathological liar or similar factors.
f) Emotional weakness resulted by family problems, hatred, revenue, and love.
4. The Interviewer’s Personal Traits.
a) He must be a practical psychologist who understands the human psyche and behavior.
b) He has a sincere interest in people. People who are reclusive generally are not good interviewers.
c) He is clam, has self-discipline, and keeps his temper.
d) He is courteous, decent and sensitive.
e) He is self-assumed and professional. He is tactful, i.e. he knows what to say when and how to say it.
f) He is cordial and agreeable, and never officious. But he should avoid over-familiarity it.
g) He is forceful, persistent and patient. Some people just cannot be rushed.
h) He is analytical.
i) He is flexible and cautious.
j) He is a good actor and can conceal his own emotion.

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k) He avoids third degree tactics and never deviates from the fundamental principle that a person must be
treated according to humanitarian and legal precepts.
l) he keeps the rules of evidence in mind.
5. Planning the Interview.
In planning the interview, the interviewer should consider:
a) The facts of the case which have been established so far.
b) The information needed to complete the picture
c) The sources of information that may be consulted such as files and records.
d) The possibility of confronting the suspect with physical evidence .
e) The time available for the interview.
f) The time allowed by law.
6. Preparation of the Interview –Before interviewing a witness, the law enforcer should mentally review the case
and consider what information the witness can contribute. If the case requires it, he should acquaint himself with
the background of the witness.
7. Time, Place and Surrounding Circumstance.
a) It is not always possible to fix the time and place of an interview, but since memory is short, it is basic that an
interview with the witness and suspect(s) should take place as soon as possible after the commission of the
crime.
b) Interview of arrested person should be made as soon as possible after the arrest.
c) Conduct interviews whenever possible in your own turf, i.e. your office.
d) Have an interview room where there will be privacy. It should be a plain room but not bleak. There should be
few furniture, and no distracting pictures, calendars or similar items.
e) Arrange it so that there will be no interruption during the interview.
f) Suspects should be interviewed separately and out of sight and earshot of each other.
g) If are two interviewers, let one man be the prime interviewer.
h) Arrange chairs so that window light falls on the interviewee and not on the interviewer.
i) The interviewer should adapt his speech to the style best understood by the subject. In dealing with tan
uneducated subject, the interviewer should use simple words and sentences.
j) Straight-back chairs should be used for both subject and interviewer. Other types of chairs induce slouching
or leaning back, and such position are not conductive to proper interviews.
k) The interviewer should remain seated and refrain from pacing about the room.
8. Opening the Interview.
a) The interviewer should identify himself and the agency to which he belongs.
b) He should try to size up the interviewee and reach to tentative conclusion about his type, then use the best
interview approach.
c) He should keep in mind the provisions of law regarding rights of people under custodial investigation.
9. The Body of the Interview.
a) The interviewee should be allowed to tell his own story in his own words without interruption.
(i) This allows for continuity and clearness.
(ii) Range of interview is broadened.
(iii) It helps the interviewee recall and relate evens in their proper order.
b) Interviewer should keep to the point at issue and should not wander too far from it.
c) Interviewer should be alert for hearsay information so he can question the interviewee on the matter later.
d) Do not interrupt a trend of ideas by abruptly asking a question. Use the uninterrupted account of the witness
interview
e) However, you may guide the interviewee innocuous questions such as, “And then what did you do?”
10. Questioning.
a) Dominate the interview. Be careful, do not allow the interviewee to be the one asking the questions.
b) Do not ramble. Have a reason for every question asked.

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c) Follow the order of time and bring out the facts in that order. This technique is called “chronological
questioning” and is considered the easiest as people tend to think in terms of what happened first, the,
second, then third. The interviewer should go step by step in learning all the details concerning the planning
and commission of the crime and what happened after it was committed.
d) Exhaust each topic before moving on to the next.
e) Determine the basis for each material statement. It might be a hearsay.
f) Keep your questions simple and understandable. Avoid double-edged or forked questions.
g) The dangers of leading and misleading questions should be borne in mind. A question which suggests to the
witness the answer which the interviewer desires is a leading question. Questions which assume material
facts that have not been proven are misleading questions.
h) Wait for the answer to one question before asking a second one.
i) Ask important questions in the same tone of voice as the unimportant ones.
j) As a rule, avoid trick or bluffing questions.
k) Where it is necessary to inquire into the past history of the interviewee involving something unpleasant, it is
wise to use introductory remarks deploring the need for the question and saying that it is one of the
unpleasant but necessary of an officer.
11. Closing
a) Before closing the interview, the law enforcer should make a mental check of the purpose of the interview
and should analyze what he has learned, then decide whether he has attained his objective. He should be
guided in this respect by the 5 W’s and I H- what, where, when who, why and how.
b) The interviewer should always the door open for a re-interview. Don’t forget to say “THANK YOU” after the
interview.
Note: Although the words “interview” and “interrogation” have similar meanings, there are those
who prefer to use “interview” when questioning witness and informants, and “interrogation” when
questioning suspects.
A Philosophy of Interview and Interrogation:
The RIGHT officer, Asking the RIGHT questions, In the RIGHT manner, At the RIGHT time and in the
RIGHT place, Will get the RIGHT answers.
INTERROGATION IN GENERAL
1. Interrogation Defined. An interrogation is the questioning of a person suspected of having committed an offense
or of a person who is reluctant to make a full disclosure of information in his possession which is pertinent to the
investigation.
2. Purpose of Interrogation
a) To obtain information concerning the innocence or guilt of suspect.
b) To obtain a confession to the crime from a guilty suspect.
c) To induce the suspect to make admissions.
d) To know the surrounding circumstances of a crime.
e) To learn of the existence and location of physical evidence such as documents or weapons.
f) To learn the identity of accomplices
g) To develop information which will lead to the fruits of the crime.
h) To develop additional leads for the investigation
i) To discover the details of any other crime in which the suspect participated.
3. Preliminary Conduct. –The interrogator should identify himself a t the outset and state in general the purpose of
the interrogation. He must advise the suspect of his rights against self-incrimination and inform him that he does
not have to answer questions and that, if he does answer, these answers can be used as evidence against him.
he must inform the suspect of his right to counsel and that a state appointed counsel will be made available

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without cost to him if he so desires. No questioning of the suspect unless the latter has definitely waived his right
to be silent. Ordinarily the investigator should be alone with the suspect and, of course, the latter’s lawyer, if he
has requested counsel.
4. The Interrogation Room –The room should provide freedom from distractions. If should be designed simply to
enhance the concentration of both the interrogation and the subject on the matter under questioning.
5. Interrogation Techniques –The following are some of the techniques practiced by experienced investigators:
a) Emotional Appeals –Place the subject in the proper frame of mind. The investigator should provide emotional
stimuli that will prompt the subject to unburden himself by confiding. Analyze the subject’s personality and
decide what motivation would prompt him to tell the truth, then provide those motives through appropriate
emotional appeals.
b) Sympathetic Approach – The suspect may fell the need for sympathy or friendship. He is apparently in
trouble. Gestures of friendship may win his cooperation.
c) Kindness –The simplest technique is to assume that the suspect will confess if he is treated in a kind and
friendly manner.
d) Extenuation –The investigator indicates he does not consider his subject’s indiscretion a grave offense.
e) Shifting the Blame –The interrogator makes clear his belief that the subject is obviously not the sort of person
who usually gets mixed up in a crime like this. The interrogator could tell from the start that he was not
dealing with a fellow who is a criminal by nature and choice. The trouble with the suspect lies in his little
weakness –he like liquor, perhaps, or he is excessively fond or girls or he has had a bad run of luck in
gambling.
f) Mutt & leff –Two (2) agents are employed. Mutt, the relentless investigator, who is not going to waste any
time because he knows the subject, is guilty. Jeff, of the other hand, is obviously a king-hearted man.
CRIMINAL INTERROGATION SYSTEMS
1. Types of Offenders and Approaches to be used in Dealing With Them:
a) Emotional Offenders have a greater sense of morality. They easily feel remorse over what they have done.
The best approach in interrogating this type of offender is the sympathetic approach.
b) Non-Emotional Offenders normally do not feel any guilt, so the best way to interrogate them is through the
factual analysis approach, that is, by reasoning with the subject and letting him know that his guilt has
already been, or will soon be, established.
2. Interrogation of Suspect Whose Guilt is Definite or Reasonably Certain
a) Maintain an attitude that shows that you are sure of yourself when you conclude that the subject is indeed
guilty.
(i) Don’t be very friendly with the subject and do not offer a handshake.
(ii) At the outset, accuse the subject of lying. If he reacts with anger, this usually indicates innocence. But if
he remains calm, you can generally conclude that your suspicion of guilt confirmed.
(iii) Interruption of questioning by the subject may indicate innocence. Silence is equated is equated with
guilt.
(iv) Do not allow the subject to repeatedly deny his guilt.
(v) Assume that the subject is guilty and proceed to ask why he committed the act,.
(vi) When interrogating a “big shot,” it may be useful to lower his status by addressing him by his first name,
instead of using a title of respect.
(vii) Remember that one who is trained in criminal interrogation is easier to question than an ordinary
criminal since he ahs less confidence in himself as a liar.
b) The subject should be made aware of the fact that the interrogator knows information indicating his guilt and
that the interrogator is not merely “fishing” for evidence.
c) Let the subject know that he is showing signs of deception, some of which are:
(i) Pulsation of the carotid (neck) artery
(ii) Excessive activity of the Adam’s apple
(iii) Avoiding the eyes of the interrogator, swinging one leg over the other foot wiggling, wringing of the
hands, tapping of fingers, picking fingernails, etc.
(iv) Dryness of the mouth

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(v) Swearing to the truthfulness of assertions. Guilty subjects to strengthen their assertions of innocence
frequently use this.
(vi) “Spotless Past Record” –“Religious Man.” These are asserted to support statements, which the subject
knows, and realizes the interrogator knows, to be false.
(vii) A “Not That I Remember” or “As Far As I Know” expression should be treated as a veiled admission or
half-truth.
d) Sympathize with the subject by telling him that anyone else under similar conditions or circumstances might
have done the same thing.
e) Reduce the subject’s guilt feeling by minimizing the moral seriousness of his offense.
f) In order to secure the initial admission of guilt, the interrogator should suggest possible reasons, motives or
excuses to the subject.
g) Sympathize with the subject by:
(i) Condemning his victim. During the questioning, the interrogator should develop the notion that the initial
blame, or at least some the blame, for the crime rests upon the victim.
(ii) Condemning the subject’s accomplice. But the interrogator must be cautious so that the subject as
leniency or exculpation from liability does not misinterpret his comments.
(iii) Condemning anyone else upon whom some degree of moral responsibility might be placed for the
commission of the crime.
h) In encouraging the subject tot ell the truth display some understanding and sympathy.
(i) Show sympathy through a pat on the shoulder (usually reserved for men who are either younger that or
of the same age as the interrogator, or emotional offenders), or gripping the subject’s hand. Care must
be taken with female offenders, who might consider any physical contact with the interrogator as a
sexual advance.
(ii) Tell the subject that even if he was your own brother (or any other close relative), you would still advise
him to speak the truth.
(iii) Convince the subject tot ell the truth for his own moral or mental well being
(iv) The “friendly-unfriendly” act. This is much like the Mutt and Jeff system discussed earlier. The only
difference is that this act seems more effective if done by a single interrogator playing both roles.
i) Point out the possibility of exaggeration on the part of the accuser or victim or exaggerate the nature and
seriousness of the offense itself.
j) Early in the interrogation, have the subject situate himself at the scene of the crime or in some sort of contact
with the victim or the occurrence.
k) Seek an admission of lying about some incidental aspect of the occurrence by achieving this, the subject
loses a great deal of ground, bringing him nearer to the confession stage, because he can always be
reminded by the interrogator that he has not been telling the truth.
l) Appeal to the subject’s pride well-selected flattery or by a challenge to his honor. Flattery is especially
effective on women subjects.
m) Point out the uselessness of lying.
n) Point out to the subject the grave consequences and futility of a continuation of his criminal behavior.
o) Rather than seek a general admission of guilt, first ask the subject a question regarding some detail of the
offense, or inquire as to the reason for its commission.
p) When co-offenders are being interrogated and the previously described techniques have been ineffective,
play one against the other. This is effective because when two or more persons have collaborated in the
commission of a criminal offense and are later apprehended for questioning, there is usually a constant fear
on the part of each participant that one of them will “talk,” in exchange for some leniency or clemency.
3. Interrogation of Suspect Whose Guilt is Uncertain
a) Ask the subject if he knows why he is being questioned.
b) Ask the subject to relate all he knows about the crime, the victim, and possible suspects.
c) Obtain from the subject detailed information about his activities before, during and after the occurrence under
investigation. This is a good method of testing the validity of the subject’s alibi.
d) Where certain facts suggestive of the subject’s guilt are known, ask him about them rather casually and as
though the real facts were not already known, to give the subject an opportunity to lie. His answer will furnish
a very good indication of his possible guilt or innocence, and if he is guilty, his position becomes very
vulnerable when confronted with the facts possessed by the interrogator.

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e) At various intervals, ask the subject certain pertinent questions in a manner, which implies that the correct
answers, are already known.
f) Refer to some non-existing incriminating evidence to determine whether the subject will attempt to explain it;
if he does, that is an indication of guilt.
g) Ask the subject whether he ever thought about committing the offense or one similar to it. If the subject
admits he had thought about committing it, this fact is suggestive of his guilt.
h) In theft cases, if the suspect offers to make restitution, that fact is indicative of guilt.
i) Ask the subject whether he is willing to take a lie-detector test. the innocent person will almost always
immediately agree to take practically any test to prove his innocence, whereas the guilty person is more
prone to refuse to take the test or to find excuses for not taking it, or for backing out of his commitment to
take it.
j) A subject who tells the interrogator, “All right, I’ll tell you what you want, but I didn’t do it,” is, in all probability,
guilty.
4. General Suggestions Regarding the Interrogation of Criminal Suspects
a) Interview the victim, the accuser, or the discoverer of the crime before interrogating the suspect.
b) Be patient and persistent. Never conclude an interrogation at a time when you feel discouraged and ready to
give up; continue for a little while longer.
c) Make no promises when asked, “What will happen to me if tell the truth?” A promise of leniency or immunity
may induce an innocent to confess.
d) View with skepticism the so-called conscience-stricken confession.
e) When a subject has made repeated denials of guilt to previous investigators, first question him, whenever
circumstances permit, about some other, unrelated offense of a similar nature of which he is also considered
to be guilty.
f) An unintelligent, uneducated criminal suspect, with a low cultural background should be interrogated on a
psychological level comparable to that usually employed in the questioning of a child.
5. Interrogation Witnesses and Other Prospective Informants:
a) Give the witness or prospective informant an assurance that the offender will not harm him or any member of
his family, and that there is a witness protection program specially designed to meet that contingency when it
becomes necessary.
b) If such witness or prospective informant refuses to cooperate with the police, try to sever any bond between
him and the offender, and proceed to interrogate the witness or informant as if he were the suspect.
A. DEVELOPMENT AND CONTROL OF INFORMANTS
1. Confidential Informant Defined – a confidential informant is an individual who supplies information on a
confidential basis with the understanding that his identity will not be made known.
a) Scientific approach in criminal investigation can assist law enforcers immeasurably, but there is always that
one case wherein the crime laboratory cannot help. This is the reason why investigators must to know the
man on the street, then man who can supply information.
b) Law enforcers must develop confidential informants everyday.
2. Need for Informants
a) Informants increase accomplishment in all areas of investigation.
b) Without confidential informants, the officer’s source of information is limited to what he gets through formal
interview.
c) Informants enable law enforcers to infiltrate the criminal element and help lower criminal morale. Advance
information improves crime prevention and enables the police to find out the identity of transient hoodlums.
d) Informants are an investigative “short cut’ to solve cases, to recover stolen property, and to make
apprehensions.
3. Where to Find Criminal Informants and Whom to Develop
a) Legitimate persons and criminals

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(i) Hoodlums, criminals, fences, bookies, barbers, bartenders, poolroom and dancehall operators,
prostitutes, madams, pawnbrokers, cab drivers, bell hops, service station attendants, waitresses and
others. A class in themselves is persons who had been accused or suspected of a crime.
(ii) Persons engaged in certain occupations should be considered.
4. How to Develop Confidential Informants
a) Constant need.
(i) No matter what our scientific development might be, there will always come that time when we will need
informants.
(ii) Development of confidential informants should therefore be a continuous process.
b) Evaluation of the individual being considered as possible informant:
(i) Does he have access to information?
(ii) Can he develop the trust of his associates?
(iii) Intelligence and physical courage
(iv) His criminal record and background
(v) His pattern of behavior
c) Basic considerations.
(i) Contact must be made in a neutral place. The officer making the contact should not be in uniform or in
police vehicles. Contact should be made in such a manner that the informant’s association with the law
enforcement agency would not be disclosed. Get the informer away from his local habitat to a place
where he is not known. Call him by phone and let him set the time and place.
(ii) Plan the interview as to the type of “approach.”
[1] Return of favor. –Even small favors can help a lot in developing informants. These may be extended
in various ways.
[2] Monetary consideration –There may be ties when an officer has to pay for information. one must
make sure he gets his money’s worth. Do not overpay or you will have a professional informant.
[3] Appeal to prospect’s ego. –Men on the beat (patrolmen/investigators) have a good opportunity of
developing informants.
[4] Development of “friendship” helps because the informant respects the officer. –This is accomplished
by friendly acts of the officer to the possible informant himself or his relatives.
[5] Involvement in illegal activity –The illegal activity serves as pressure on the possible informant. The
attitude toward him, though, should be “Put up or get out”.
[6] Fear motive. –This is fear of the police or of his associates
[7] Revenge motive
[8] Perverse motives –To eliminate competition, for example.
[9] Bad publicity –Especially applicable to businessmen
(iii) Officer’ Ability.
[1] Develop an informant to the point that he really respects you. - Do not call hour informant a “stool
pigeon” or a “stoolie” when talking to him.
[2] Secrecy in contacts cannot be over-emphasized. It helps maintain the confidence of the informant.
You may use fictitious names over the phone. Contact should be discreet and the meeting place
frequently changed.
[3] The informant may expect a few favors in return. –Make him understand that you association with
him does not give him the license to operate illegally. You must have him understand also that he
is not an employee of the police even though he is being paid for the information. It may be
necessary to hold something over his head.
- Be sure that your informant does not brag about his association with you
- Make sure he is giving you good information. test him with facts you know.
- Do not allow yourself to be interviewed by an informant.
Give him the facts he needs to know, and nothing more.
5. Use of Informants
a) Maximum benefit. – The confidential informant should be used for the maximum benefit of the entire
organization, not of only one (1) officer/investigator.

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b) A designated executive should be aware of the identity of the informant. –At least two (2) individuals in the
law enforcement agency should know the identity of a confidential informant. This gives him the feeling that
he is really cooperating with the police. It is also possible that something might happen to you, which would
mean the loss of the informant to the entire police force. Besides the officer who developed the informant, it
is suggested that the other be a rank-officer to give the informant a feeling of importance.
c) Consider a program within your respective commands for the development of informants.
(i) Keep records as to the ability of your men to develop informants.
(ii) Keep records as to the accomplishments of each of the informants. This should tell you who among the
informants should be discarded.
(iii) Keep records as to fugitives apprehended, loot recovered and cases given to you.
(iv) Maintain a tickler system to review your informant’s contribution to your command.
B. UNDERCOVER INVESTIGATION
1. Preparation for undercover work should be sufficiently thorough:
a) To preclude compromise
b) To minimize danger to the undercover operative
c) To ensure the ultimate success of the investigation
2. Undercover investigation should not be attempted until other investigative techniques have failed or are
deemed impractical.
3. Factors to consider before undercover investigation is initiated:
a) The exact result desired
b) Jurisdiction
c) The importance of the investigation
d) Available planning information
e) Availability of qualified personnel
f) The equipment and preparation necessary
g) Danger to the investigator involved.
4. General and Specific Qualifications –Undercover work as a selective assignment requires that the investigator
possess, in addition to certain general qualifications, specific qualifications required in the type of investigation
being conducted.
a) General qualifications:
(i) Well-trained and experienced
(ii) A calm, collected and resourceful individual with good judgment and wit
(iii) Complete self-confidence to feel absolutely certain that he can successfully play the part of the
character he will assume.
(iv) Courage and ability to meet unforeseen situations with quick, sound decisions
(v) Will power to avoid drugs and excessive use of intoxicants.
(vi) Ability to avoid unwise entanglements with women involved in the case or associated with the subject.
b) Specific qualifications
(i) Ability to act out an assumed role
(ii) Good memory in an investigation in which no notes can be taken or report submitted.
(iii) Skill adaptable to the occupation assumed.
(iv) Physical appearance and capabilities consistent with his assumed qualifications.
(v) Well-grounded in the lingo and techniques of the subject criminal operations
(vi) In special situations, the undercover investigator should possess certain linguistic abilities, hobbies,
sports, musical talent and personal background for the particular and undercover assignment.
5. Authority for undercover operations must be from the top officer of the organization, for this requires coordination
with other agencies.

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6. The fewest number of persons must know the undercover operation. Otherwise, the investigation or the
operative himself might be jeopardized.
7. The background or cover story regarding the assumed identity of the undercover operative must be such that
he can easily win the confidence of the suspect or organization sought to be infiltrated, and should seldom be
wholly fictitious.
8. Badge and credentials must never be carried.
9. A weapon should only be carried if it is consistent with the background story.
10. Provide safe communication systems between the undercover agent and headquarters relaying information or
instructions.
11. Arrangements for drops and safe houses must be made and, if necessary, the undercover operative himself
may be placed under surveillance.
12. The undercover operative must never pose as a criminal unless no other approach appears adequate.
13. The role of the undercover operative is to gather information or evidence against the suspect(s) or the
organization, never to instigate the commission of a crime.
14. Plans for the operation must provide actions or alternatives in case the undercover is arrested.
15. Reminders tot he undercover operative:
a) Act as natural as possible.
b) Do not overplay the part.
c) Do not indulge in any activity, which is not in conformity with the assumed identity.
d) Do not make notes unless they are to be mailed or passed immediately: (Use codes and never place return
address in letters and envelopes).
e) Do not use intoxicants except to play the part.
f) Limit association with women to that necessary to play the part
C. SURVEILLANCE
1. In General. –In the investigation of a certain case, a point is reached when the investigator sometimes finds it
difficult to secure leads through questioning of the complainant and witnesses. In such a situation, the investigator
has to go to the filed to locate the criminal or, if he is known, to study his habits, movements and possible
accomplices in the commission of the crime.
2. Definition –Surveillance is the discreet observation of places, persons and vehicles for the purpose of obtaining
information concerning the identities or activities of subjects.
3. Objectives of Surveillance:
a) To detect criminal activities
b) To discover the identity of persons who frequent the establishment and determine their relationship.
c) To discern the habits of a person who lives in or frequents the place.
d) To obtain evidence of a crime or to prevent the commission of a crime.
4. Shadowing or Tailing. It is the act of following a person. Its objectives are:
a) To detect evidenced of criminal activities.
b) To establish the association of a suspect
c) To find a wanted person
d) To protect a witness
There are three (3) types of shadowing employed, depending upon the objective of the surveillance:

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a) “Loose Tail” is employed when a general impression of the subject’s habits and associates is required.
b) “Rough Shadowing” without special precautions may be used where the criminal must be shadowed and
he is aware of this fact; or where the subject is a material witness and must be protected from harm or
other undesirable influences.
c) “Close Tail” surveillance is one is which extreme precautions are taken against losing the subject.
5. Tactics. – The subject should be kept unaware that he is being shadowed. The investigator should be
inconspicuous. He should not be detected looking directly at the suspect. He should shift from left to right, never
remaining for long directly behind the subject. Both sides of the street should be used. If the tail, he should
request immediate removal from the statement.
6. Note. –The investigator must maintain a note or log containing a chronological record of the activities of both the
investigator and the subject. The log can be used either in the interrogation of the suspect or for purposes of
cross-examination during trial.
7. “Roping”or Undercover Work. –It is a form of investigation in which the investigator assumes a different and
unofficial identity (a cover story) in order to obtain information. The general objective of an undercover
investigation is to obtain more information.
8. Arrest of Undercover Agent. –If the police arrest an investigator, he must act in accordance with his orders. If he
has not received orders regarding the disclosure of his identity in case of arrest by other law enforcement officers,
he must act according to his judgement. In such a case, if retaining his assumed character does not serve a
useful purpose, the investigator should refuse to make a statement except to a member of his own organization.
9. Preparation and Supervision of Discreet Surveillance
a) Familiarize participating operatives with the case.
(i) Use sketches, photos and maps in the briefing.
(ii) Make a physical description of the subject(s).
(iii) Anticipate contingencies that arise and plan what to do
(iv) Ready coins for bus or jeepney fare and for making phone calls
(v) Determine exits and have them covered.
(vi) Bear in mid the need to secure a Search Warrant on short notice.
(vii) Ready materials for recording surveillance
(viii) Pre-arrange signals.
(ix) Maintain contact among the participants.
(x) Rotate participants and apportion their distances.
(xi) Consider the possibility of counter-surveillance.
b) Choosing proper equipment. Equipment include motor vehicles, boats, binoculars, camera, radio equipment,
handcuffs, containers for evidence, strips of neolith and other materials for disguising motor vehicles (day or
nighttime), firearms, tear gas etc.
Standard Methods of Recording Investigative Data
a) Photographs;
b) Sketching crime scenes;
c) Written notes (what you have seen or observed);
d) Developing and lifting fingerprints found at the crime scene:
e) Gathering physical evidence;
f) Plaster cast;
g) Tape recording of sounds;
h) Video tape recording of objects; and
i) Written statements of subjects(s) and witnesses

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Scientific Examination of Real Evidence
a) The Crime Scene Search
Processing and Securing a Crime Scene –Processing a crime scene includes the application of diligent
and careful methods by an investigator/policeman to recognize, identify, preserve and collect facts and items
of evidentiary value that may assist in reconstructing that which actually occurred. The crime scene is the
area surrounding the place where the crime occurred. the processing of the area at the scene includes all
direct traces of the crime. and this is determined by the type of crime committed and the place where the act
occurred.
Protecting the Crime Scene and the Evidence –Successful crime scene processing, depends upon the
policeman’s or investigator’s skill in recognizing and collecting facts and items of value as evidence, and
upon his ability to protect, preserve, and later, to present these in a logical manner. This requires making
careful and detailed notes and sketches; using correct procedures in taking photographs of the scene; taking
written statements and transcribing verbal statements of witnesses, suspects and marking and preservation
of collected physical objects of evidentiary nature.
b) Laboratory examination of objects and substances located usually at the crime scene Objects and
substances needing examination in some cases are carried, intentionally or unintentionally, by suspects from
the crime scene.
Investigator’s Notebook.
a) Purpose: Considering the mass of details and the number of cases which in some instances an investigator
is handling, it is very possible that he might forget some details. Many of the details associated with the
investigation, while not essential to the report, might become points of interest to the court when the case is
brought to trial. Experienced investigators employ a handbook to record the relevant details of the case.
During trial, the court allows investigators to consult their notes to refresh their memory.
b) Recording Notes: The data of the investigation should be recorded in a complete, accurate and legible
fashion so that in the event another investigator is required to assume the responsibility for the investigation,
be can make intelligent use of the notebook.
Custodial Investigation/Interrogation.
It is the skillful questioning of a suspect or a hostile witness to divulge information on the crime being
investigated. It must be remembered, however, that police investigators cannot learn proper interrogation merely
by reading books. The success of interrogation depends on its legality, topic, physical insight and experience.
PROCEDURE AT THE CRIME SCENE
Upon Arrival at the Crime Scene
a. Record time/date of arrival at the crime scene, location of the scene, condition of the weather, condition and
type of lighting direction of wind and visibility
b. Secure the crime scene by installing the crime scene tape or rope (police line)
c. Before touching or moving any object at the crime scene determine first the status of the victim, whether he
is still alive or already dead. If the victim is alive the investigator should exert effort to gather information from
the victim himself regarding the circumstances of the crime, while a member of the team or someone must
call an ambulance from the nearest hospital. After the victim is remove and brought to the hospital for
medical attention, measure, sketch, and photograph. Only a coronal or a medical examiner shall remove the
dead body unless unusual circumstances justifies its immediate removal.
d. Designate a member of the team or summon other policemen or responsible persons to stand watch and
secure the scene, and permit only those authorized person to enter the same.
e. Identify and retain for questioning the person who firs notified the police, and other possible witnesses.

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f. Determine the assailant through inquiry or observed him if his identity is immediately apparent. Arrest him if
he still in the vicinity.
g. Separate the witnesses in order to get independent statements.
Recording - As a rule, do not touch, alter or remove anything at the crime scene until the evidence has been
processed through notes, sketches and photographs, with proper measurements.
Searching for Evidence
a) A general survey of the scene is always made, however, to the location of obvious traces of action, the
probable entry and exit points used by the offender(s) and the size and shape of the area involved.
b) The investigator examines each item encountered on the floor, walls, and ceiling to locate anything that may
be of evidentiary value. You should:
i. Give particular attention to fragile evidence that may be destroyed or contaminated if it is not
collected when discovered.
ii. If any doubt exists as to the value of an item, treat it as evidence until proven otherwise.
iii. Ensure that the item or area where latent fingerprints may be present is closely examined and that
action taken to develop the prints.
iv. Carefully protect any impression of evidentiary value in surfaces conducive to making casts or
molds. If possible, photograph the impression and make a cast or mold.
v. Note stains, spots and pools of liquid within the scene and treat them as evidence.
vi. Treat as evidence all other items, such as hairs, fiber, and earth particles, foreign to the area in
which they are fund –for example, matter found under the victim’s fingerprints.
vii. Proceed systematically and uninterruptedly to the conclusion of the processing of the scene. The
search for evidence is initially completed when, after a thorough examination of the scene, the
rough sketch, necessary photograph and investigative note have been completed and the
investigator has returned to the point from which the search began. Further search may be
necessary after the evidence and the statements obtained have been evaluated.
c) In large outdoor areas, it is advisable to divide the area into strips about four (4) feet wide. The policeman
may first search the strip on his left he faces the scene then the adjoining strips.
d) It may be advisable to make a search beyond the area considered to be immediate scene of the incident or
crime. For example, evidence may indicate that a weapon or tool used in the crime was discarded or hidden
by the offender somewhere within a square-mile area near the scene.
e) After completing the search of the scene, the investigator examined the object or person actually attacked by
the offender.
Methods of Crime Scene Search
A. Strip Search Method In this method, the area is blocked out in the form of a rectangle. The three (3)
searchers A, B, and C proceed slowly at the same place along paths parallel to one side of the rectangle.
When a piece of evidence is found, the finder announces his discovery and the search must stop until the
evidence has been cared for. A photographer is called, if necessary. The evidence is collected and tagged
and the search proceeds at a given signal. At the end of the rectangle, the searchers turn and proceed along
new lanes.
B. The double strip or grid method of search is a modification of the Strip Search Method. Here, the
rectangle is traversed first parallel to the base then parallel to a side.
C. Spiral Search Method - In this method, the three searchers follow each other along the path of a spiral,
beginning on the outside and spiraling in toward the center.
D. Zone Search Method - In this method of search, the area is considered to be approximately circular. The
searchers gather at the center and proceed outward along radii or spokes. The procedure should be
repeated several times depending on the size of the circle and number of searchers. One shortcoming of this
method is the great increase in the area to be observed as the searcher departs from the center.

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Collecting Evidence. This is accomplished after the search is completed, the rough sketch finished and photographs
taken. Fragile evidence should be collected as they are found. All firearms (FAs) found to have tampered serial
numbers (SNs) shall be automatically subjected to macro etching at the Philippine National Police Crime Laboratory
(PNP-CL). A corresponding report to the Firearms and Explosive Office (FEO) must be made for verification purposes.
In the collection, the investigator should touch the evidence only when necessary.
Removal of Evidence. The investigator places his initials, the date and the time of discovery on each item of evidence
and the time discovery on each item of evidence for proper identification. Items that could not be marked should be
placed in a suitable container and sealed.
Tagging or Evidence. Any physical evidence obtained must be tagged before its submission to the evidence
custodian.
Evaluation of Evidence. Each item of evidence must be evaluated in relation to all other evidence, individually and
collectively.
Preservation of Evidence. It is the investigator’s responsibility to ensure that every precaution is exercised to
preserve physical evidence in the state in which it was recovered/obtained until it is released to the evidence
custodian.
Releasing the Scene. The scene is not releases until all processing has been completed. The release should be
effected at the earliest practicable time, particularly when an activity has been closed or its operations curtailed.
Sketching Crime Scenes.
Pointers to Consider:
a) To establish admissibility, the investigator must have had personal observation o the data in question. In
other words, the sketch must be sponsored or verified.
b) REMINDER: Sketches are not a substitute for notes or photos; they are but a supplement to them.
c) Types of sketches: Floor plan or “bird’s-eye view”; Evaluation drawing; Exploded view; and Perspective
drawings.
d) Write down all measurements.
e) Fill in all the detail on your rough sketch at the scene. Final sketch may be prepared at the office.
f) Keep the rough sketch even when you have completed the final sketch.
g) Indicate ht North direction with an arrow.
h) Draw the final sketch to scale.
i) Indicate the PLACE in the sketch as well as the person who drew it. Use the KEY –capital letters of the
alphabet for listing down more or less normal part sof accessories of the place, and numbers for items of
evidence
j) Indicate the position, location and relationship of objects.
k) Methods or systems of locating points (objects) on sketch
 Rectangular coordinates. (Measurements at right angels from each of two walls)
 Coordinates constructed on transecting base line. Choose relatively fixed points for your baseline.
 Triangulation. (Measurements made from each of two fixed objects to the pint you want to plot or locate
so as to form an imaginary triangle. Sketch will show as many imaginary triangles as there as object
plotted).
l) Two (2) investigators should check critical measurements, such as skid marks.
m) Measurements should be harmony; or in centimeters, inches, yards, meters, mixed in one sketch.
n) Use standard symbols in the sketch.
o) Show which way doors swing,
p) Show with arrow the direction of stairways.
q) Recheck the sketch for clarity, accuracy, scale, and title key.

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GENERAL TYPE OF SKETCH
Rough Sketch- made at the crime scene, no scale, proportion ignored and everything is approximate
Finished Sketch- for courtroom presentation, scale and proportion are strictly observed.
Kinds of Sketch
1. Sketch of locality gives a picture of the crime scene in relation to its environs including neighboring
buildings, roads, etc.
2. Sketch of grounds includes the crime scene and its nearest environment, ex a house w/ a garden
3. Sketch of details describes the immediate crime scene only.
SCENE OF CRIME OPERATION (SOCO)
Composition of SOCO Team
The SOCO team is composed of but not limited to the following depending on the nature of the case:
1. Team Leader
2. Assistant team leader
3. Photographer and photographic log recorder
4. Sketcher and Evidence Recorder
5. Evidence Recorder
6. Evidence Recovery Personnel
7. Driver/Security
Personnel Functions and Responsibility
1. Team Leader
a. Assume control of the crime scene. Ensure the safety of personnel as well as the victim and offenders
caught in the scene and secure the crime scene from kibitzers.
b. Conduct initial survey of the crime scene for evaluating potential evidence and narrative description of
the place.
c. Determine search patterns to be used and designate assignments to evidence gatherer.
d. Designate command post location in or near the crime scene and insure exchange of information
between searcher and investigator.
e. Coordinate with other law enforcement agencies for the security of the victims, offenders/suspects and
the scene of the crime.
f. Ensure that sufficient supplies and equipments are made available for personnel involved in SOCO.
g. Control access to the scene and designate personnel. To log persons entering the place and remove
Kibitzers in the area,
h. Continuously reevaluate efficiency of the search ensure and that all places are searched properly.
i. Release the crime scene to the investigators handling the case
2. Assistant Team Leader
a. Shall assist the team Leader in all his functions and responsibilities.
b. Assume/takeover the responsibilities of the Team leader in his absence
3. Photographer and photographic log recorder:
a. Photograph the entire area of the crime scene with overall medium and close-up coverage using
appropriate scale.
b. Photograph victims, suspects/offenders arrested in the scene.
c. Photograph all evidences before collection.

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d. Photograph all latent Fingerprints, impressions before lifting or casting is made. Likewise, photograph
blueprints map and other items
e. Prepare photograph log photographic sketch.
4. Sketcher:
a. Perform all sketches necessary during the crime scene processing.
5. Evidence Recorder/Custodian:
a. Prepare evidence recovery log and accomplish chain of custody of evidence.
b. Conduct packaging, preservation and transportation of gathered evidence to the Crime Laboratory.
c. Coordinate evidence nomenclature with sketcher, photographer and evidence gatherer.
d. Receive and record all evidence recovered.
e. Maintain custody and control of evidence
f. Observe the proper custody of evidence
g. Coordinate transmittal of evidence to case investigator or to Crime Laboratory per agency guidelines.
6. Evidence Recovery Personnel:
a. Have significant evidence photograph before it is collected.
b. Keep team leader always apprised of significant evidence located.
c. Initial and date all evidence and turn it over to the evidence recorder/custodian after noting where the
item was located.
d. Coordinate evidence nomenclature with evidence recorder/custodian and sketch prepared.
e. Ensure that appropriate safety measures are adhered to especially with respect to proper clothing
including gloves.
Equipment
1. Basic Equipment - Crime Scene tape or Rope (Police Line), Measuring device e.g. ruler and measuring
tape, Recording materials e.g. chalk, sketcher and paper pad, Camera with film, Video camera or tape
recorder, Evidence collection kit, Flashlight
2. Evidence Containers - String tags-large and small, Evidence tape or masking tape, Roll of manila paper for
wrapping, Plastic gallon, ½ pint bottles/vials-plastic and glass, ¼ pint bottles/vials-plastic glass, Absorbent
cottons, Rolls of fingerprint tape, Plastic bags-different sizes, Paper bags-different sizes
3. Tools - Pair of scissors, Knife-heavy duty and folding knife, Adjustable wrench, Pliers, Wire cutter, Complete
screw driver set, Saw, Hammer, Ax of hatchet, Shovel, Fingerprint magnifier, Nylon brush, Magnet, Spatula,
Box of plaster of Paris for casting or lifting foot marks, Goggles, Sifting screen, Funnels of different sizes,
Ladder, Hand lens of magnifier, Weighting scale, Vernier caliper and micrometer, Scalpels
4. Evidence Gathering Equipment - Rubber glove and cotton, Box or filter, White cotton sheet, Cotton balls and
swabs, Fingerprint car, data card and ink cards, Photo data card, Black and white latent print lifting cards,
Rolls of lifting card, Complete magna brush kit, Complete dusting kit, Heavy duty rubber lifters, Camera whit
no wide angel, normal and macro lens, Arson kit, Casting and molding kit, Electric engraver
5. Miscellaneous - Rubber bands, Pencil, ball pens, pentel pen-different color, Chalks, Permanent flat marker,
Eraser, Stapler with extra staple, Assorted paper clip and binders, Notebooks, paper pads, sketch pads and
drawing pads, Drawing compass, Clippers, Magnetic directional compass, Carbon papers and coupon
bonds.

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INTERVIEW IN GENERAL
Interview Defined. - An interview is the questioning of a person believed to possess knowledge that is in official
interest to the investigator.
Importance of Interview. - Interview in crime investigation is very important considering that the person interviewed
usually gives his account of an incident under investigation or offers information concerning a person being
investigated in his own manner and words.
Basic Assumptions: Nobody has to talk to law enforcers. No law compels a person to talk to the police if he does
not want to. Therefore, people will have to be persuaded, always within legal and ethical limits, to talk to law
enforcers. This makes interviewing an art:
The Person Interviewed (Consider the following)
g) His ability to observe.
h) His ability to remember
i) His ability to narrate.
j) His mental weakness because of stupidity or infancy
k) His moral weakness because of drunkeness, drug addiction, his being a pathological liar or similar factors.
l) Emotional weakness resulted by family problems, hatred, revenue, and love.
The Interviewer’s Personal Traits
m) He must be a practical psychologist who understands the human psyche and behavior.
n) He has a sincere interest in people.
o) He is clam, has self-discipline, and keeps his temper.
p) He is courteous, decent and sensitive.
q) He is self-assumed and professional. He is tactful, i.e. he knows what to say when and how to say it.
r) He is cordial and agreeable, and never officious. But he should avoid over-familiarity it.
s) He is forceful, persistent and patient. Some people just cannot be rushed.
t) He is analytical.
u) He is flexible and cautious.
v) He is a good actor and can conceal his own emotion.
w) He avoids third degree tactics and never deviates from the fundamental principle that a person must be
treated according to humanitarian and legal precepts.
x) he keeps the rules of evidence in mind.
SCIENTIFIC AIDS TO CRIMINAL INVESTIGATION
The scientific tools a criminal investigator can use are:
a. Fingerprinting (Dactyloscopy)
b. Photography
c. Forensic Chemistry
d. Medico-legal
e. Forensic Ballistics
f. Questioned documents examination
g. Polygraphy
h. DNA Analysis

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DNA: THE LATEST SCIENTIFIC TOOL
Deoxyribonucleic Acid (de– ak– si– ri– bo– n(y)u– kle– ik) - is a chemical substance
found in all cells of living organism whose composition have been passed on from parents to
offsprings. It is called as the genetic or hereditary material. A person’ s DNA is the SAME in
every cell. It is contained in blood, semen, skin cells, tissue, organs, muscle, brain cells, bone,
teeth, hair, saliva etc.
Chemically, it is an acid and is composed of three sub-units, namely:
1. the phosphate group
2. a deoxyribose sugar, and
3. one of the four bases – Adenine (A), Thymine (T), Cytosine (C) and Guanine (G)
FROM THE WHOLE TO THE (MICROSCOPIC) PARTS
The There Each One The Genes are
human is a nucleus chromosome chromosomes segments
body nucleus contains 46 of every are filled of DNA
contains inside chromosomes pair with that contain
100 each arranged is from tightly instructions
trillion human in 23 each coiled to make
cells cell pairs parent strands proteins
of the building
DNA blocks of life
BIOLOGICAL EVIDENCE AMENABLE FOR DNA ANALYSIS
 blood and bloodstains
 semen and seminal stains
 hair with follicle/root
 saliva and buccal cells
 tissues and skin cells
 organs
 bone marrow and bones
 teeth
LINE UP OF CASES WHERE DNA ANALYSIS MAYBE USEFUL
 Sexual assault cases like RAPE
 Murder
 Homicide
 Robbery

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 Hit and run
 Extortion
 Paternity cases
 Identification of remains in mass disaster
IDENTIFYING DNA EVIDENCE
EVIDENCE Possible location of
DNA on the evidence
Source of DNA
baseball bat or similar
weapon
handle, end sweat, skin, blood, tissue
hat, bandanna, or mask inside sweat, hair, dandruff
eyeglasses nose or ear pieces, lens sweat, skin
facial tissue, cotton swab surface area mucus, blood, sweat, semen,
earwax
dirty laundry surface area blood, sweat, semen
toothpick tips saliva
used cigarette cigarette butt saliva
stamp or envelope licked area saliva
tape or ligature inside/outside surface skin, sweat
bottle, can, or glass sides, mouthpiece saliva, sweat
used condom inside/outside surface semen, vaginal or rectal cells
blanket, pillow, sheet surface area sweat, hair, semen, urine, saliva
“through and through bullet outside surface blood,tissue
bite mark person’s skin or clothing saliva
fingernail, partial fingernail scrapings blood, sweat, tissue

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COLLECTION OF DNA EVIDENCE
BLOOD Liquid
Liquid
Person
Scene
Collect in EDTA tubes.
a. Use syringe, collect into EDTA tube.
b. Transfer onto cotton cloth. Air dry.
BLOOD Clot Scene a. Collect clot in test tube.
b. Transfer onto cotton cloth. Air dry.
BLOOD Wet
Wet
Wet
Clothing
Object
Water
Air dry at room temperature. Package in paper bag.
Air dry at room temperature. Package in paper bag.
Collect sample with syringe. Place sample in plastic
container. Freeze sample.
DRIED
BLOOD
Crust
Stain
Person, Scene,
Object
Weapon
Scrape crust into paper packet. Collect control blank.
Collect item directly.
EVIDENCE CONDITION LOCATION COLLECTION MODE
DRIED
BLOOD
Stain
Stain
Stain
Spatters
Small object
Vehicle,Uphol-
stery,Carpet,
Wallpaper,Wood
Unmovable surface,
concrete wall
Unmovable surface
Collect entire item.
Cut out stained area. Package separately. Collect
control.
a. Scrape into paper packet. Collect control.
b. Transfer onto moistened cotton thread. Air dry thread.
Tape lifting. Place in container.
SEMEN Liquid
Liquid
Wet
Dried stain
Victim
Object, Scene
Clothing
Clothing, Carpet
Upholstery
Unmovable surface
a. Collect sample with rape kit.
b. Collect sample with swabs.
Keep in refrigerator.
a. Collect liquid semen into tube.
b. Transfer onto cotton cloth.
Air dry.
Air dry. Package separately.
Collect as is. Package separately.
Cut out section with stain. Collect control.
Scrape sample into paper packet.
Collect control.

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HOW IS DNA TYPING DONE?
DNA typing or profiling is a procedure wherein DNA extracted from the evidentiary sample as well as from
the reference biological samples obtained from the victim and suspect are analyzed and processed to generate a
particular pattern or profile for each samples. This profile is unique for each person except from identical twins. The
patterns are compared either with that of a known individual to determine a match, or a set of possible relatives to
determine consanguinity.
In individual identification, the pattern obtained from the evidentiary sample is compared with that of a
suspect. If the patterns are different, definitely it has not originated from the suspect. If it is SIMILAR, the probability
that the evidentiary sample arose from the suspect and not from a random individual in the population is calculated
using a formula based on well-accepted concepts of statistical probabilities and population genetics.
In cases of determining consanguinity, DNA from the subject and his/her relatives are analyzed and
compared. DNA fragments of an individual are contributed by his/her father and mother. Identification of mass
disaster victims are done in the same way, the DNA of unidentified victim and relatives are analyzed and compared. In
paternity cases, the DNA fragment contributed by the father should be observed in the alleged father. Then, the
probability that the alleged father is the father of the child is calculated as a ratio between that of the alleged father and
any random male in the population.
There are several types of DNA tests that can be performed. The NBI currently employs the PCR-based
testing using the Short Tandem Repeats (STR) systems like PE-ABI Profiler and Promega’s PowerPlex 16 and
PowerPlex Y Systems of analysis.
STAGES OF DNA ANALYSIS
 EXTRACTION –to obtain the DNA material from the specimen. Two commonly used methods are Chelex,
DNA IQ (rapid methods) and organic extraction.
 QUANTITATION - to determine the amount of DNA material extracted from the sample. NBI make use of
the QUANTIBLOT kit which is human specific and highly sensitive up to picogram level.
 DNA AMPLIFICATION by PCR (Polymerase Chain Reaction)–to make many copies of specific DNA
fragment. PCR is a synthesis reaction that is repeated for a number of cycles and results in exponential
EVIDENCE CONDITION LOCATION COLLECTION MODE
URINE Liquid Person Direct deposit in container. Keep refrigerated.
SALIVA Liquid Scene Use syringe transfer into test tube. Keep refrigerated.
TISSUE,
ORGAN
BONE
Fresh
Dried
Scene
Scene
Place in container. Keep refrigerated.
Place in container.
HAIR With tissue
With blood
Intact hair
Fragments
Control
Scene
Scene
Scene
Scene
Person
Collect hair with tissue in container. Keep refrigerated.
Separate hair from blood. Air dry. Collect in paper
packet.
Pick up sample with clean forceps. Place in paper
packet.
Tape lift. Package in container.
Pulled (at least 20).

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accumulation of the specific DNA fragment. The thermal cycler is the machine that does this PCR and is
compared to a Xerox machine.
Admissibility of DNA evidence
Under the rules of evidence, expert opinion on specialized knowledge must be relevant to the question at issue;
that is, it must assist the trier of fact to understand the evidence or to determine a fact in issue. For instance, in the
Daubert case earlier referred to, two minor children and their parents sought to recover damages for birth defects
which were allegedly caused by the mother’s prenatal ingestion of Bendectin, an anti-nausea drug sold by the
defendant pharmaceutical company. After discovery, the defendant moved for summary judgment, asserting that
Bendectin does not cause birth defects in humans.
Defendants submitted an opinion from a well-credential expert stating that his review of all of the literature on
Bendectin revealed nothing to indicate that the drug was capable of causing birth defects in humans. So the issue
before the court was what standard would be used for admitting expert scientific testimony in a trial before a federal
court. The US Supreme Court held that the standard should be “If scientific, technical, or other specialized knowledge
will assist the trier of fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or
education may testify thereto in the form of an opinion or otherwise.” This is the standard laid down in Rule 702 of the
Federal Rules of Evidence in the US. Our own Rules of Court in the Philippines follows this standard with respect to
the admission of opinion evidence.
In short, expert opinion based on the scientific method must be (1) relevant to the fact in issue, and (2) must be
scientifically valid, as tested by the four indicia noted above. Relevance requires a valid scientific connection to the
pertinent area of inquiry so that it will be admitted as evidence.
In the Philippines, the admissibility of DNA evidence was squarely raised in the celebrated case of People v.
Hubert Webb, et. al. (Criminal Case No. 95-404, Regional Trial Court, Branch 274, Parañaque City). This case
involved a sinister plan to gang rape the teen-aged victim. The accused, 7 of them, went to the house of the victims
after midnight on June 29, 1991 and by a pre-arranged plan with the principal witness, three of them entered the
house. According to this witness, after three of the accused had entered the house, she too went inside and pushing a
door leading to one of the rooms, she saw two bloodied bodies on top of the bed, and on the floor she saw the first
accused with bare buttocks on top of the rape victim, pumping her. She also saw the second accused at the foot of the
bed where the two bodies lay, which was about to wear his jacket. She saw the rape victim moaning and in tears, and
her mouth was gagged. It was further found by the trial court that when the first accused was raping the victim, her
seven year-old sister was awakened and, upon seeing her elder sister being raped, she jumped at the first accused, bit
his shoulder, grabbed his hair, and pulled down his leather jacket. The first accused became furious, grabbed the
young girl, pulled her to the wall, and stabbed her several times. The medico-legal officer of the NBI found that the
mother of the rape victim was stabbed 12 times after having been hog-tied with an electric cord like the younger
daughter. The rape victim was found positive for spermatozoa in the genital area in the smear test conducted by the
NBI laboratory although it was noted that there were no injuries therein. At the time the cadaver of the rape victim was
discovered, she was found naked from the waist down; and it bore contusions on the left and right thighs, which meant
that she had put up a severe resistance to an unwanted sexual intercourse. The wounds on the younger sister also
indicated that she was able to ward off her assailant.
It can be seen from this recitation of facts in the decision of the trial court that there were various sources of
DNA evidence which could have been presented by either the prosecution or the defense. Aside from the spermatozoa
found on her genitalia by the NBI’s smear test, it was found that the younger sister of the victim bit the shoulder of the
first accused and grabbed his hair. So the police investigators could have examined her teeth as well as the strands of
hair of the accused to gather DNA evidence. Unfortunately, nothing of this sort was done by the police. As for the
sperm sample obtained by the NBI laboratory, the first accused wanted to present this as evidence for the defense at
the trial, but the prosecution objected on the ground that this has been degraded at the time of the trial, which was held
from August, 1995 to February 1998. The trial court sustained the objection of the prosecution, and the defense let it
rest at that. Thus, the opportunity to use DNA evidence to conclusively prove the guilt or the innocence of the accused
was lost. This case has been appealed to the Supreme Court with both sides predicting victory. The defense of the
accused was alibi. While we all know that alibi is a weak defense, it must be noted that in this case, the first accused
presented an array of witnesses as well as documentary evidence to prove that he was in California at the time of the
commission of the crime. The other accused also depended on alibi for the defense. A total of 95 witnesses were
presented by the accused to support their defense, while the prosecution presented 7 witnesses. The decision in this

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case is so controversial that the Supreme Court has decided to hear it en banc, as it has required the accused to
furnish 19 copies of their briefs (People v. Hubert Webb, G.R. No. 141859).
Admissibility of DNA evidence under Philippine Law
Under our laws, evidence is admissible when it is relevant to the fact in issue and is not excluded by the Rules
(Rule 128, sec. 2, Rules of Court). Under this test, evidence is relevant when it has such a relation to the fact in issue
as to induce belief in its existence or non-existence. Evidence, to be relevant, need not conclusively prove the ultimate
fact in issue, but only have any tendency to make the evidence of any fact that is of consequence to the determination
of the point in issue more probable or less probable than it would be without the evidence. DNA evidence would be
invaluable as corroborative evidence without statistical backup if the accused has been identified by other proof. It
would be proper to inform the court that two DNA samples match or do not match. In the case of a match, this makes it
probable that the DNA in the sample come from the same person suspected as a perpetrator. It would be corroborative
even without the statistical back up needed in the Frye test or under the Federal Rules of Evidence. In case of a non-
match, this may lead to the acquittal of a suspect. The probability under this form of presentation would be in an
amount that is not precisely known. This is because the only criterion we are using is that of relevancy.
Evidentiary facts are relevant in evidentiary rules where there is such a rational and logical connection between
them and the matter in issue that proof of the former logically tends to make the latter more probable or improbable –
that is, where the fact offered in evidence has a legitimate tendency to establish the truth concerning a controversial
issue (Francisco, Revised Rules of Court (Evidence) 1964, p. 40, citing Jones on Evidence, p. 240). Under our Rules,
even collateral matters are allowed when they tend in any reasonable degree to establish the probability or
improbability of the fact in issue (Rule 128, sec. 4). With such liberal rules of evidence, there should not be any doubt
as to the admissibility of DNA profiles in our courts, even without the support of population genetic statistics.
Thus, in a prosecution for abusos deshonestos, our Supreme Court held that it was not error for the trial court to
convict the defendant on the basis of a finding of the Bureau of Science that the substance taken from the sex organ of
the defendant showed that he was suffering from gonorrhea, like the complaining witness who was infected with the
disease as a result of the crime (U.S. v. Tan Teng, 23 Phil. 145 [1912)]). This shows that even a mere finding from the
government bureau which shows a match between the disease of the defendant and that of the complaining witness
can be considered relevant under our rules, as it tended to show the probability of the defendant’s physical contact
with the complaining witness.
Even in the United States under the Frye test, some courts have admitted DNA match profiles without the
statistical back up. The Pennsylvania Supreme Court held that “the factual evidence of the physical testing of the DNA
samples and the matching alleles, even without the statistical conclusions, tended to make the appellant’s presence
more likely than it would have been without the evidence, and was therefore relevant” (Commonwealth v. Crews, 640
A2d 395 [1994]).
Our rules of evidence are all based on probabilities. “The most that can be reached is a high probability that the
fact in question is true,” says Wharton, for “it is impossible even to expound the principles and method of induction, as
applied to natural phenomena, in a sound manner, without resting them upon the theory of probability” (Wharton,
Criminal Evidence, cited in Francisco, id. at 48). “We have, therefore, to content ourselves with partial knowledge –
knowledge mingled with ignorance producing doubt. Even scientific conclusions cannot be demonstrated except so far
as they deal with abstrations” (ibid.).
“Probabilities have been with us for years, and a statement of a probability is, by its nature, a statement of
partial knowledge, so it is paradoxical to imply that in principle we cannot calculate the probability of an
event without further empirical knowledge” (MacKnight, “The Polymerase Chain Reaction (PCR): The
Second Generation of DNA Analysis Method Takes the Stand”, 9 Santa Clara Computer & High Tech.
L.J. 287 (1993) at 328).
Of course, the loose relevancy in our rules does not augur well for the protection of the rights of the accused.
Scientific evidence tends to mystify even the hard-boiled judges who are ignorant of DNA technology. The scientific
jargon may overwhelm them into admitting DNA evidence and give these frill credence, unless the accused hires his
own expert to challenge the findings. If the defense counsel fails to challenge the weight of such evidence because of
ignorance of the procedures for validation, cross-checking and re-testing, or if he fails to challenge the premise of the
expert witness, the accused would remain at the mercy of the prosecution expert. The relevancy standard in evidence
implicitly relies on the effectiveness of the adversarial system and on the right of cross-examination to protect the rights

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of the accused. Failure of the defense counsel to question the findings of the prosecution expert will place the accused
at the short end of due process. The defense counsel in a situation like this should at least have an idea about
laboratory testing and sampling procedures, population genetics, reliability of statistics, and laboratory error rates. The
accused should have the logistics to hire his own expert so that he can be placed on an even keel with the prosecution.
As for expert opinion on DNA profiles, our rules of evidence admit such opinion as long as the witness proves
that he is an expert in a given field. And he can do this by proving that he has knowledge, skill, experience, training, or
education in any given field (Rule 130, sec. 49). Of course, the difficult problem is that the presentation of DNA
evidence requires different forms of expertise. The presenter may have to present a laboratory technician, a molecular
biologist, a population statistician, and a geneticist. This is because the laboratory technician may not be qualified to
testify on molecular biology, the biologist may not be able to testify on statistical probabilities on the frequency of a
random match, and the statistician may not be qualified to testify on population genetics. Thus, in Powell v. State (598
SW2d 829 (1994)), the defendant challenged the expertise of the molecular biologist to testify on the probabilities of
matching DNA patterns because he was not qualified as a population geneticist. (See also Swanson v. State, 823
SW2d 812 [1992]). In State v. Lewis, (654 So2d 761 [1995]), the trial court denied expert status to a lab technician who
presented herself as an expert in molecular biology; the appellate court reversed because she belonged to invitational
professional organizations, received several academic awards, had written 14 articles on DNA analysis, and had been
assistant director of a laboratory for more than one year.
The other problem here is that there are only a few experts in the pertinent fields. Experts in statistics, genetics,
biology, organic and inorganic chemistry, computers, laboratory testing and protocols, on human hair and sperm, blood
and bloodstains, etc. would be needed in this kind of inquiry. They are rare birds, especially here in the Philippines.
They therefore do not come cheap, and engaging their services would add to the high cost of DNA profiling and
testing, which has been estimated to cost at least P30,000 at pre-devaluation rates. A poor defendant may not have
access to such experts. This raises constitutional issues of due process and violation of the rights of the accused. He
may not get a fair trial if he cannot engage the services of such an expert witness. Since most defendants in heinous
crimes like rape and murder are generally poor, they would not have the resources to pay for their own experts or to
import them from abroad. This would result in a one-sided contest in our criminal justice system.