Transcript Chapter 1 Introduction to Forensic Science Forensic Science

Chapter 1
Introduction to Forensic
Science
Forensic Science

Application of science to law

Begins at crime scene

Also known as Criminalistics
History of Forensics
Alphonse Bertillon

Father of Criminal
Identification

Developed
ANTHROPOMETRY
Anthropometry

Series of body
measurements
to distinguish
between
individuals
Francis Galton
 Studied
fingerprints &
how to classify
them
Calvin Goddard
 Firearms
examiner
 Studied bullet
comparison
(Done today with a
comparison
microscope)
Edmond Locard
 Started
the 1st crime lab (France)
 Developed
Principle
the Exchange
Locard’s Exchange Principle

When 2 objects come into contact,
there is an exchange of materials
between them
(Cross-transfer of evidence)

Criminals can be connected to a
crime by particles carried from the
crime scene
Crime Laboratories
A. National
B. State
C. Local
National Labs (4)
1.
2.
3.
4.
Federal Bureau of Investigation
(FBI  largest lab in the world)
Drug Enforcement Administration
(DEA)
Bureau of Alcohol, Tobacco,
Firearms, & Explosives (ATF)
U.S. Postal Inspection Service
State Labs
 Service
the state as well as
local communities that cannot
afford their own crime lab
Local Labs

Service counties & municipal (cities)
agencies

Financed by local government

Nassau & Suffolk County Crime Labs
Basic Crime Lab Services
1.
2.
3.
4.
5.
Physical Science Unit
Biology Unit
Firearms Unit
Document Examination Unit
Photography Unit
Physical Science Unit
 Uses
chemistry,
physics, and
geology to identify
& compare
evidence
Biology Unit

Examines blood & other body
fluids

DNA profiles

Compares hair & fibers

Examines botanical materials
(plants/wood)
Firearms Unit (Ballistics)

Examines firearms, discharged bullets,
cartridge cases, & shotgun shells

Searches clothing for gunpowder
residue

Determines distance a weapon was
fired from
Document Examination Unit
 Studies
handwriting or typewriting
 Analyzes
paper & ink
 Examines
indented writings &
burned documents
Photography Unit
 Examines
&
records physical
evidence
 Only
black & white
photos are shown
to jurors
Optional Services
1.
2.
3.
4.
5.
Toxicology Unit  poisons/drugs
Latent Fingerprint Unit
Polygraph Unit  lie detector
Voiceprint Analysis Unit
Evidence Collection Unit  CSI
Evidence & the Courts
Frye vs. United States (1923)
 Rejected
 Scientific
lie detector evidence
techniques, procedures,
& principles must be “GENERALLY
ACCEPTED” by majority of
scientific community
Daubert vs. Merrell Dow
Pharmaceuticals (1993)

“GENERAL ACCEPTANCE” is no
longer absolute

Trial judge will act as GATEKEEPER
 deciding whether evidence is
admissible or not
The Expert Witness

A person with
knowledge that is not
expected from the
average individual

This is acquired
through experience,
training, education, or
a combination of all 3
Testimony

Ordinary witnesses cannot & must
not give their opinions  just FACTS

Expert witnesses can give their
opinions based on scientific facts (but
can’t be biased to either side)
Other Areas of
Forensic Science
Forensic Pathology
 Investigates
sudden, unnatural,
unexplained, or violent deaths
 Tries
to answers Who? What?
When? Why? How?
 Via
Autopsy
Types of Death
 Natural
 Accidental
 Homicide
 Suicide
 Undetermined????
Estimating Time of
Death
Rigor Mortis

Muscles shorten
& body stiffens

Appears within
24 hours

Disappears
within 36 hours
Livor Mortis
 Blood
settles to
areas closest
to ground
 Skin
turns a
blue/purple
color
Algor Mortis
 Body
starts to lose heat
 1-1.5°F
per hour until room or
outside temperature is reached
Potassium Levels

Rise in ocular (eye)
fluid after death

Time of death
estimated by amount
of potassium present
Forensic Anthropology

Identifies &
examines human
skeletal remains

Determines race,
sex, age, & injuries

Creates facial
reconstructions
Forensic Entomology
 Studies
insects
& their relation
to death
 Blow
flies lay
eggs 
maggots
Forensic Psychiatry
 Determines
if people are
competent enough to make
decisions or stand trial
 Develop
behavioral profiles
Forensic Odontology
 Studies
teeth &
bite marks
 Useful
when a
body is
unrecognizable
Forensic Engineering

Determines how
a crime
happened & who
is responsible

Accident
reconstruction