2. The science that is applied to the law and
criminal proceedings.
It applies the knowledge and technology
of science for the definition and
enforcement of criminal and civil law.
Often referred to as criminalistics
What is forensic science?
3. They have the
ability to supply
accurate and
objective
information that
reflects the
events that have
occurred at a
crime.
Why is the forensic scientist so
important to the justice system?
4. NO!!!
Possible needs include:
◦ Burglary
◦ Counterfeiting/art forgery/document forgery
◦ White collar crime (embezzlement, etc.)
◦ Computer crime
◦ Auto accident
◦ Arson
◦ Drug enforcement
◦ Terrorism
◦ ETC….
Is Forensic Science only applied to
cases involving homicides?
5. Crime labs are not typical to one type of
model because they can vary in:
◦ Size
◦ # of employees
◦ Who runs them (ex: police department,
prosecutor/D.A.’s office, universities, or
independent agencies in the government)
◦ Services they provide
Currently there are over 320 public crime
labs
Organization of a Crime Lab
6. A typical crime lab has two sets of
personnel:
◦ Field analysts - investigators that go to crime
scenes, collect evidence, and process the
scene.
◦ Laboratory analysts - scientists or other
personnel who run tests on the evidence once
it is brought to the lab (i.e., DNA tests, or
bullet striations).
Organization of a Crime Lab
7. In the United States, crime labs may be
publicly or privately operated, although
private laboratories typically do not
respond to crime scenes to collect
evidence.
Public crime labs are organized at the city,
county, state, or national level.
Organization of a Crime Lab
8. The federal government has no single law
enforcement or investigative agency that
has unlimited jurisdiction.
4 major federal crime labs have been
created that extend beyond the
jurisdictional boundaries of state and local
forces.
Organization of a Crime Lab
9. 1. FBI –maintains the world’s largest crime
lab
2. Drug Enforcement Administration Labs
(DEA) – responsile for analysis of drugs
seized in violation of federal laws
3. Bureau of Alcohol, Tobacco, and Firearms
– responsible for analyzing alcoholic
beverages and documents relating to tax law
enforcement
4. U.S. Postal Inspection Service – concerned
with criminal investigations relating to the
postal service
Federal Crime Labs
10. Physical Science Unit
◦ Applies principles and techniques of
chemistry, physics, and geology.
◦ Examination of items as diverse as
drugs, glass, paint, explosives, and soil.
Biology Unit
◦ Staffed with biologists and biochemists for DNA
profiling of dried bloodstains and other bodily
fluids, comparison of hair and fibers, &
identification and comparison of botanical
materials such as wood and plants
Basic Services
11. Firearms Unit
◦ Examination of firearms, discharged
bullets, cartridge cases, shotgun shells, and
ammunition of all types is conducted
◦ Garments and other objects are also examined
in order to detect firearm discharge residues
Document Examination Unit
◦ Handwriting and typewriting on questioned
documents are studied to ascertain authenticity
and/or source.
◦ Analysis of paper and ink
Basic Services
12. Photography Unit
◦ Examine and record physical evidence
◦ Use of digital imaging, infrared, ultraviolet, and
X-ray photography, to make invisible
information visible to the naked eye.
Basic Services
13. Toxicology Unit
◦ Body fluids and organs are examined to
determine the presence/absence of drugs and
poisons
Latent Fingerprint Unit
◦ Processing and examining evidence for latent
fingerprints
Polygraph Unit
◦ Lie detector
◦ Essential tool of the criminal investigator
Optional Services
14. Voiceprint Analysis Unit
◦ Used for cases involving telephoned threats or
tape-recorded messages to tie the voice to a
particular suspect.
Evidence-Collection Unit
◦ Dispatches specially trained personnel (civilian
and/or police) to the crime scene to collect and
preserve physical evidence.
Optional Services
15. The role of the forensic scientist is
twofold:
◦ to analyze physical evidence found on a victim
on the scene of a crime and
◦ compare it to evidence found on a suspect and
to provide expert testimony in a court of law.
Role of the Forensic Scientist
16. Because their work product may ultimately
be a factor in determining a person’s guilt or
innocence, forensic scientists may be
required to testify with respect to their
methods and conclusions at a trial or
hearing.
In this case, they are considered an expert
witness (an individual whom the court
determines possesses knowledge relevant to
the trial that is not expected of the average
layperson.
Role of the Forensic Scientist
17. Forensic Pathology
◦ Involves the investigation of
sudden, unnatural, unexplained, or violent
deaths.
◦ If a cause cannot be found through
observation, an autopsy is normally performed
to establish the cause of death.
Additional Forensic Services
18. After a human body expires, it goes through several
stags of decomposition.
Stages of Death:
◦ Rigor Mortis – shortening of muscle tissue and stiffening
of body parts in the position they are in when death
occurs
Manifests within the first 24 hours and disappears
before 36 hours
◦ Livor Mortis – settling of blood in areas of the body
closest to the ground
Early stages of decomposition
Due to the heart stop pumping
◦ Algor Mortis – body temperature continually cools after
death until it reaches the ambient of room temperature
Rate of heat loss due to location, body size, victim’s
clothing, and weather conditions
Heat loss: 1-1.5°F / hour
Forensic Pathology
19. Another helpful method to determine time
of death is to determine potassium levels
in ocular fluid (vitreous humor)
After death cells within the inner surface
release potassium into the vitreous humor
(this rate approximates the T.O.D.)
Forensic Pathology
20. Concerned primarily with the identification
and examination of human skeletal
remains
An examination of bones can reveal
origin, sex, approximate age, race, and
skeletal injury.
Also assist in creating facial
reconstructions to aid in the i.d. of
skeletal remains or mass disasters (i.e.
plane crash)
Forensic Anthropology
21. The study of insects and their relation to a
criminal investigation.
Used to estimate the time of death
Forensic Entomology
22. Specialized area in which the relationship
between human behavior and legal
proceedings is examined
Retained for both civil and criminal
litigations
Forensic Psychiatry
23. Provide information for the identification
of victims when the body is left in an
unrecognizable state
Teeth are composed of enamel, the
hardest substance within the body and
therefore have a resilience that will
outlast tissues and organs as
decomposition begins
Also used in bite mark analysis (i.e. case
of Ted Bundy)
Forensic Odontology
24. Concerned with failure analysis, accident
reconstruction, and causes and origins of
fires or explosions
Forensic Engineering
