This document provides an introduction to the Philippine criminal justice system, focusing on crime detection and arrest procedures. It discusses how crimes are typically detected by victims reporting to police or police discovering crimes. Important parts of detection include aggressive police work like buy-bust operations, where undercover officers pose as buyers to catch suspected drug dealers in the act. The document also outlines the legal definitions and procedures for making arrests, including when arrests require warrants versus when they can be made without warrants based on probable cause. It provides details on citizens' arrests and different types of warrants like alias and John Doe warrants.

1. INTRODUCTION TO
PHILIPPINE CRIMINAL
JUSTICE SYSTEM
CLJ100

2. Crime Detection
What is crime detection in relation to the
administration of CJS?
◦Through crime detection, the police are typically
the first component of the justice system to deal
with the commission of the crime.

3. How is crime detected?
 The most typical way that crimes come to the attention of the
police is for the victim to report its occurrence to the police.
 A less typical way for the police to be advised of the crime is
through the reporting of someone who has witnessed its
commission or has come upon evidence indicating that a crime
has been committed.
 The police themselves, through their proactive routine
operations discover that a crime has been committed or witness
its commission.

4. What is the most important part of crime
detection?
An important part of crime detection may be the result of
an aggressive police work. Experienced police officers and
detectives sometimes concentrate their surveillance
operations and investigate efforts on persons, situations, or
places in which past experience has taught them that
criminal behavior is likely." Example, conducting a buy-bust
operation.

5. What is a buy-bust operation?
“Buy-bust operation’’ is also known in legal and police parlance as a
form of “entrapment”. This simply means that ways and means are
resorted by the police officers in order to catch a law violator as
distinguished from “instigation” wherein the police basically induced
the person into committing a crime.
◦ In entrapment, the person caught by the police is criminally liable
for the crime committed; while in instigation, the person induced
is not criminally liable but the police officer who induced the
latter may be held criminally, civilly and administratively.

6. ENTRAPMENT
1. The criminal design originates
from and is already in the mind
of the lawbreaker even before
entrapment;
2. the law enforcers resort to
ways and means for the purpose
of capturing the lawbreakers in
flagrante delicto and,
3. this circumstance is no bar to
prosecution and conviction of
the lawbreaker.
INSTIGATION
1. the idea & design to bring
about the commission of the
crime originated and developed
in the mind of the law enforcers;
2. the law enforcers induce, lure,
or incite a person who is not
minded to commit a crime and
would not otherwise commit it,
into committing the crime; and
3. this circumstance absolves the
accused from criminal liability.

7. ENTRAPMENT & INSTIGATION
INSTIGATION
Suspecting that Juan was a drug pusher,
SPO2 Mercado, leader of the Narcom team,
gave Juan Php 100 bill and asked him to
buy some marijuana cigarettes. Desirous of
pleasing SPO2 Mercado, Juan went inside
the shopping mall while the officer waited
at the corner of the mall. After 15 minutes,
Juan returned with 10 sticks of marijuana
cigar w/c he gave to SPO2 Mercado who
thereupon placed Juan under arrest and
charged him with violation of the
Dangerous Drug Law by selling marijuana
cigarettes.
ENTRAPMENT
A, an anti-narcotic agent of the
Government acted as a poseur buyer of
shabu and negotiated with B, a suspected
drug pusher who is unaware that A is a
police officer. A then issued marked money
to B who handed a sachet of shabu to B.
Thereupon, A signaled his anti-narcotic
team to close-in and arrest B. This is a case
of entrapment because the criminal mind
is in B already when A transacted with him.

8. ARREST
Section 1. Definition of arrest. — Arrest is the taking of a person into custody in order that he
may be bound to answer for the commission of an offense. (1)
Section 2. Arrest; how made. — An arrest is made by an actual restraint of a person to be
arrested, or by his submission to the custody of the person making the arrest.
No violence or unnecessary force shall be used in making an arrest. The person arrested shall not
be subject to a greater restraint than is necessary for his detention. (2a)
Section 3. Duty of arresting officer. — It shall be the duty of the officer executing the warrant to
arrest the accused and to deliver him to the nearest police station or jail without unnecessary
delay. (3a)
Section 4. Execution of warrant. — The head of the office to whom the warrant of arrest was
delivered for execution shall cause the warrant to be executed within ten (10) days from its
receipt. Within ten (10) days after the expiration of the period, the officer to whom it was
assigned for execution shall make a report to the judge who issued the warrant. In case of his
failure to execute the warrant, he shall state the reasons therefor. (4a)

9. Section 5. Arrest without warrant; when lawful. — A peace officer or a private person may, without a warrant,
arrest a person:
(a) When, in his presence, the person to be arrested has committed, is actually committing or is attempting to
commit an offense;
(b) When an offense has just been committed, and he has probable cause to believe based on personal knowledge
of facts or circumstances that the person to be arrested has committed it; and
(c) When the person to be arrested is a prisoner who has escaped from a penal establishment or place where he is
serving final judgment or is temporarily confined while his case is pending or has escaped while being transferred
from one confinement to another.
Section 6. Time of making arrest. — An arrest may be made on any day and at any time of the day or night. (6)
Section 7. Method of arrest by officer by virtue of warrant. — When making an arrest by virtue of a warrant, the
officer shall inform the person to be arrested of the cause of the arrest and of the fact that a warrant has been
issued for his arrest, except when he flees or forcibly resists before the officer has opportunity to so inform him, or
when the giving of such information will imperil the arrest. The officer need not have the warrant in his possession
at the time of the arrest but after the arrest, if the person arrested so requires, the warrant shall be shown to him as
soon as practicable. (7a)
Section 8. Method of arrest by officer without warrant. — When making an arrest without a warrant, the officer
shall inform the person to be arrested of his authority and the cause of the arrest, unless the latter is either engaged
in the commission of an offense, is pursued immediately after its commission, has escaped, flees or forcibly resists
before the officer has opportunity so to inform him, or when the giving of such information will imperil the arrest.

10. What is Probable Cause in the Warrant of Arrest? It is defined as the facts or circumstances known by the
judge after a careful examination of the complainant and the witnesses that induced the judge to believe
without doubt that a crime was committed, and a warrant of arrest should be issued.
What is a Citizen's Arrest? A Citizen's Arrest is a warrantless arrest that can be affected by a private individual.
It is termed as a citizen's arrest if arrest is made by private individual or citizen.
What is Alias Warrant of Arrest? It is a second writ of execution replacing the first one due to expiration. A
criminal case may be archived only if after the issuance of the warrant of arrest, the accused remains at large
for six (6) months from the delivery of the warrant to the proper peace officer. An order archiving the case
shall require the peace officer to explain why the accused was not apprehended. The Court shall issue an alias
warrant if the original warrant of arrest is returned by the peace officer together with the report.
What is a John Doe Warrant? A John Doe warrant is a warrant for the apprehension of a person whose true
name is unknown. Generally, this kind of warrants is void because it violates the constitutional provision which
requires that warrants of arrests should particularly describe the person or persons to be arrested.
When is John Doe Warrant Valid? It is a warrant that is considered valid if the best description possible is
given in the arrest warrant. It must be sufficient to indicate clearly on whom it is to be served by stating his
occupation, personal appearance or peculiarities, place of residence or
other circumstances which he may be identified.