Transcript Psychology of Homicide Unit III Lecture

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Criminalistics
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Definition of Terms
*Forensic science is the
application of science to the
criminal and civil laws that are
enforced by police agencies in a
criminal justice system. In this
class we will focus on criminal
laws.
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*One of the most important contributors to
criminalistics is Edmond Locard (1877-1966) whose
main education was in law and medicine.
*Locard believed that when a person comes in
contact with and object or person, a crosstransfer of materials occur, this is called “Locard’s
exchange principle” and is the foundation of study
of forensic science.
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*An individual whom the
court determines to possess
knowledge relevant to the
trial that is not expected by
the average layperson.
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*Is a specialized area in relationship
between human behavior and legal
proceedings is examined. For criminal
cases forensic psychiatrist evaluate
behavioral disorders to determine
competency to stand trial, also examine
behavioral patterns of criminals as an aid
in developing a suspect’s behavioral
profile.
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* Biology Unit
* Biology unit-DNA, dried blood, body fluids,
hair, fibers and botanical materials (wood and
plants).
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* Firearms, discharged bullets, cartridge cases,
shotgun shells, and ammunition. Also
examination of garments and target to
determine range and angle of shot.
* Examine stippling and gas expansion.
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* Handwriting, typewriting, paper, ink,
depressions, obliterations, and erasures,
burned or charred documents.
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*Basic and digital imaging,
infrared, ultraviolet and xray photography. Also
prepared photographic
exhibits for courtroom
presentations.
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*Examines body fluids and
organs to determine the
presence or absence of drugs
and poisons. Many times
works under the direction of
the medical examiner or
coroner’s office.
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* Utilizes AFIS to examine and processes
evidence for latent fingerprints.
* Uses scientific techniques in order to produce
quality fingerprint impressions.
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* This unit dispatches specially trained
technicians to secure, collect and preserve
physical evidence.
* Specific steps to process a variety of homicide
scenes with the first priority safety, then
rendering first aid to survivors and last to process
the scene.
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*The 50% plus a feather
test. A test used to
determine evidence that
may be prejudicial or
inflammatory to the jury.
The evidence must be more
probative than prejudicial.
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* Frye v. United States (1923)-this standard
states the court must decide whether the
questioned procedure, technique, or principle
is “generally accepted” by a meaningful
segment of the relevant scientific community.
(Some court do not use the Frye Test, but
instead use the Federal Rules of Evidence, this
would include the federal courts and some
state court systems).
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* FRE-if scientific, technical, or other specialized knowledge will
assist the trier of fact to understand the evidence or to determine
a fact in issue, a witness qualified as an expert by knowledge,
skill, experience, training, or educations, may testify thereto in
the form of an opinion or otherwise, if;
* (1) the testimony is based on sufficient facts or data
* (2) the testimony is the product of reliable principles and
methods, and
* (3) the witness has applied to the principles and methods
reliability to the fact of the case.
* The gatekeeper of the evidence is the trial
judge, not only scientific evidence, but to all
expert testimony.
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* The crime scene-safety line, evidence line, one
way in and one way out. No media allowed
and admittance only on a need basis. Do not
walk on walkway. Record everyone in and out
with a log. Identify and mark all evidence.
Create sketch with accurate measurements.
Bag and tag all evidence in appropriate
containers.
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Physical evidence-tangible items. Wet biological items will
need to dry before bagging.
* Drugs
* Toxicology
* Crime scene investigation
* Hair, fibers and paint
* Arson investigation
* Explosives
* Fingerprints
* Firearms
* Fingerprints-arch, loop and whorl
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* Thank you!
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