Download Forensic Techniques

Forensic
Techniques
What is Forensic Science?
• Forensic comes from the Latin word
forensis.
• It means: for public discussion or
debate.
• Forensic science is science used in
public, in a court or in the justice
system. Any science, used for the
purposes of the law, is a forensic
science.
Forensic Scientists
• Television enhances the image of forensic
science.
• Forensic scientists are involved in all
aspects of criminal cases.
• The forensic scientist's goal is to use all
available scientific information to determine
the facts and, subsequently, the truth.
• The forensic scientist might determine:
– The validity of a signature on a will,
– If a corporation is complying with environmental
laws,
– The origin of physical evidence at a crime scene.
Forensic Scientists
Job
CIA and FBI
• The facts developed by • The forensic scientist provides
information and expert opinion
forensic scientists are
to investigators, attorneys,
based on scientific
judges, and juries which is
investigation, not
helpful in determining the
circumstantial evidence
innocence or guilt of the
accused.
or the sometimes
unreliable testimony of • Forensic scientists work
closely with police officers,
witnesses.
sheriff's deputies, prosecuting
• The work of the
and defense attorneys, DEA,
CIA, and FBI agents,
forensic scientist can
immigration workers, and
prove the existence of a
crime scene investigators, to
crime or makes
name a few.
connections to a crime.
Techniques
• Forensic scientists use a variety of
techniques in their investigations.
• The next 8 slides provide examples of
forensic techniques.
Firearms and Toolmarks
• Typically, this includes matching
bullets to the gun that fired them.
• Toolmark identification involves the
identifying characteristics between
tools, such as a pry bar, and the object
on which it is used, such as a door
frame.
• Also included in the category are
explosives and imprint evidence.
Forensic Profiling
• When a specially trained psychiatrist or
investigator can examine certain crime
scenes to come up with a personality
profile of the offender.
Document Examination
• This discipline involves all special
relationships that may exist between
document and inscription and how it
relates to a person or sequence of
events.
• This includes forgery, counterfeiting,
and handwriting analysis.
Autopsy
•
•
•
•
Done by a medical examiner
To determine cause of death
Includes external exam and photos
Followed by extensive internal exam:
– Organs are removed, weighed and
examined
– Tissues and fluids are analyzed for
abnormalities, presence of drugs, etc.
DNA Typing
• DNA code varies from one individual to
the next
• Scientists can link a strand of DNA to
an individual
• DNA can be identified from hair, blood,
or body fluid stains
• Provides powerfully compelling
evidence
Forensic Anthropology
• Examination of skeletal remains
• Tells if male or female, how the person
lived, past illness or debilitation, clues
to occupation
• Bones can tell us:
– Age at time of death
– Gender
– Race
– Height
Odontology
•
•
•
•
Teeth – no other body part lasts longer
In fires, often the only thing remaining
No two people have identical teeth
Dental records are needed to compare
to the evidence
• Teeth useful in determining a subject’s
age
Blood
• Chemical test can determine if
substance (stains) is really blood
• Another test determines if it is animal
or human blood
• Can determine gender from blood
evidence