A brief Introduction to forensic science

1. An Introduction to
Forensic Science

2. What is Forensic Science?
• …the application of science to those criminal and civil laws
that are enforced by police agencies in a criminal justice
system.

3. Forensic Science is…
• Applied Science
• Often called “criminalistics”

4. Forensic Science applies
• Chemistry
• Biology
• Physics
• Geology
Places physical evidence into a professional discipline.
to civil and criminal law
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5. The development of
Forensic Science

6. Sir Arthur Conan Doyle
• Popularized physical detection methods in a
crime scene
• Developed the character Sherlock Holmes

7. Sir Arthur Conan Doyle
• 1887 published first novel, A Study in Scarlet
• "I've found it! I've found it," he shouted to my companion, running towards us with a
test-tube in his hand. "I have found a re-agent which is precipitated by haemoglobin,
and by nothing else . . . . Why, man, it is the most practical medico-legal discovery
for years. Don't you see that it gives us an infallible test for blood stains? . . . . The
old guaiacum test was very clumsy and uncertain. So is the microscopic examination
for blood corpuscles. The latter is valueless if the stains are a few hours old. Now,
this appears to act as well whether the blood is old or new. Had this test been
invented, there are hundreds of men now walking the earth who would long ago
have paid the penalty of their crimes. . . . Criminal cases are continually hinging
upon that one point. A man is suspected of a crime months perhaps after it has been
committed. His linen or clothes are examined and brownish stains discovered upon
them. Are they blood stains, or mud stains, or rust stains, or fruit stains, or what are
they? That is a question which has puzzled many an expert, and why? Because there
was no reliable test. Now we have the Sherlock Holmes's test, and there will no
longer be any difficulty."
→ had a considerable influence on popularizing scientific crime-detection methods

8. Mathieu Orfila (1787 – 1853)
• Father of Forensic Toxicology
• 1814 - Treatise on detection of poisons & their
effects on animals.

9. Alphonse Bertillon (1853 – 1914)
• Father of Criminal Detection
• Devised the first scientific system of personal
identification, using body measurements known as
anthropometry in 1879.

10. Francis Galton (1822 – 1911)
• Conducted the first definitive study of fingerprints and their
classification.
• 1892 – Treatise entitled Finger Prints

11. Leone Lattes (1887 – 1954)
• Devised a simple procedure for determining the blood type
(A,B,O,AB) of a dried bloodstain

12. Calvin Goddard (1891 – 1955)
• Used a comparison microscope to determine if a bullet was fired
from a specific gun
• Published study of “tool marks” on bullets

13. Albert S. Osborn (1858 – 1946)
• Developed fundamental principles of document examination
• 1910 – Treatise Questioned Documents
• Was responsible for the acceptance of documents as scientific
evidence by the courts

14. Edmond Locard (1877 – 1966)
• Demonstrated how the principles
developed by Hans Gross could be
incorporated into a workable crime lab.
• Locard's exchange principle states that
once contact is made between two
surfaces a transfer of material(s) will
occur.

15. Organization of a
Crime Laboratory

16. Crime Labs
• Since the 1960's the number of crime labs increased due to
the courts demanding secure scientifically evaluated evidence.
• More crime
• More drug related crime
• Greater need for physical evidence
• Use of DNA profiling (1990’s)
Presently there are 350 Crime Laboratories in the U.S.

17. Services of the Crime Lab
• Many local crime laboratories have been created
solely for the purpose of processing evidence
• Currently most of their energy and funds are used to
analyze drugs and DNA.
• In 1932, Hoover first established a national
forensics laboratory to support all law
enforcement in the U.S.
• The oldest American forensics laboratory is in
Los Angeles, California, created in 1923 by
August Volmer.

18. Crime Lab Units
Standard
Physical Science
Biology
Firearms
Documents
Photography
Optional
Toxicology
Fingerprints
Polygraph
Voice Print
Evidence

19. Basic ServicesProvidedby
Full-ServiceCrime Laboratories
• Physical Science Unit:
• Applies the principles and techniques of
Chemistry
Physics
Geology
to the identification and comparison of crime-scene
evidence
• Biology Unit:
• Identifies dried bloodstains and body fluids
• Compares hairs and fibers
• Identifes and compares botanical materials such as wood
and plants
• Performs DNA analysis

20. Basic Services (continued)
• Firearms Unit: examines
• Firearms
• Discharged bullets
• Cartridge cases
• Shotgun shells
• Ammunition of all types
• Document Examination Unit:
• Analyzes handwriting, paper and printers of documents
• Photography Unit:
• Examines and records physical evidence at the crime scene
and at suspects' locations

21. OptionalServicesProvidedby Full-Service
Crime Labs
• Toxicology Unit:
• Examines body fluids and organs in order to determine the
presence and identification of drugs and poisons
• Latent Fingerprint Unit:
• Processes and examines evidence for latent fingerprints
• i.e. those found on surfaces
• Polygraph Unit:
• Uses lie detectors, an essential tool of the crime
investigator rather than the forensic scientist

22. Optional Services (continued)
• Voiceprint Analysis Unit:
• Involved in cases of telephone threats or tape-recorded messages
• Investigators may be able to connect a voice to a particular
suspect
• Evidence-Collection Unit:
• Incorporates evidence collection into a total forensic science
service

23. The Functions of the
ForensicScientist
• Analysis of Physical Evidence
• The forensic scientist must be skilled in applying the
principles and techniques of the physical and natural
sciences in order to identify the many types of
evidence that may be recovered during crime
investigations.
• Expert witness
• An expert witness possesses a particular skill or has
knowledge in a trade or profession that will aid the
court in determining the truth.

24. The Functions of the
ForensicScientist
(continued)
• Specially trained evidence collection technicians
□ Training in Proper Recognition,
Collection, and Preservation of
Evidence is required so that
the forensic pathologist, as the
medical examiner or coroner,
can determine the cause of
death via an autopsy.

25. Other Forensic Services
Death can be classified into five different categories:
natural death, homicide, suicide, accident or
undetermined manner of death.
• Forensic Pathology
• The cause of death can often be
determined by performing an
autopsy

26. Other Forensic Services - 2
• Forensic Pathology – continued
• After a human body expires there are several stages of
death
• Rigor Mortis
• immediately following death, the muscles relax and then become
rigid, shortening of the muscles.
• Livor Mortis
• when the human heart stops pumping, due to the blood begins to
settle in the parts of the body closest to the ground due to gravity.
The skin will appear dark blue or purple in these lower areas close
to the ground.
• Algor Mortis
• the process in which the body temperature continually cools after
death until it reaches room temperature, enabling the medical
examiner to establish the general time of death.

27. Other Forensic Services - 3
• Forensic Anthropology:
• Primarily involves the identification and examination of skeletal
remains, in order to determine if the remains are human or
another type of animal.
• If human, ethnicity, sex, approximate age, and manner of death
can often be determined by an anthropologist.

28. Other Forensic Services - 4
• Forensic Entomology
• The study of insects and their developmental stages
• Can help to determine the time of death by knowing when those
stages normally appear in the insect's life cycle

29. Other Forensic Services - 5
• Forensic Psychiatry
• The study of human behavior and legal proceedings in both civil
and criminal cases
• In civil and criminal cases, competency often needs to be
determined
• In criminal trials, the evaluation of behavior disorders is often
required in order to establish the psychological profile of a
suspect.

30. Other Forensic Services - 6
• Forensic Odontology
• An odontologist can match bite marks to a suspect's teeth, or
match a victim to his dental x-rays
• Results in an identification of an unknown individual
• Forensic Engineering
• Used to analyze construction accidents, and the causes and
origins of fires or explosions

31. Forensic Analysis
• Can include organic and inorganic analytical techniques
• Organic analysis of unknown substances
• Includes analytical techniques such as Chromatography, UV- visible
and infrared Spectrophotometry and Mass Spectrometry.
• Inorganic analysis
• Includes techniques such as the emission spectrum of elements,
Atomic Absorption Spectrophotometry, Neutron Activation Analysis,
and X-Ray Diffraction Analysis.