Chapter 2 Vocabulary
Physical Evidence
Any object that can establish that a crime has been committed or
can link a crime and its victim or its perpetrator.
Chain of Custody
A list of all people who came into possession of an item of
evidence.
Standard/Reference Sample
Physical evidence whose origin is known, such as blood or hair
from a suspect, that can be compared to crime-scene evidence.
Buccal Swab
A swab of the inner portion of the cheek; cheek cells are usually
collected to determine the DNA profile of an individual.
Substrate Control
Uncontaminated surface material close to an area where physical
evidence has been deposited. This sample is to be used to ensure
the surface on which a sample has been deposited does not
interfere with laboratory tests.
SEARCH METHODS
 Line or strip method—best in
large, outdoor scenes
 Grid method—basically a
double-line search; effective,
but time-consuming
 Zone method—most effective
in houses or buildings; teams
are assigned small zones for
searching
 Spiral method—may move
inward or outward; best used
where there are no physical
barriers
Types of Evidence
Two general types:
 Testimonial—a statement made under oath
 Direct evidence or Prima Facie evidence
 Physical—any object or material that is relevant in a
crime
 Indirect evidence
 Examples: hair, fiber, fingerprints, documents, blood, soil,
drugs, tool marks, impressions, glass.
Value of Physical
Evidence
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Generally more reliable than testimonial
Can prove that a crime has been committed
Can corroborate or refute testimony
Can link a suspect with a victim or with a
crime scene
 Can establish the identity of persons
associated with a crime
 Can allow reconstruction of events of a crime
Reconstruction
Physical Evidence is used to answer questions about:
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what took place
how the victim was killed
number of people involved
sequence of events
A forensic scientist will compare the questioned or
unknown sample with a sample of known origin.
Types of Physical Evidence
 Transient Evidence—temporary; easily changed or lost;
usually observed by the first officer at the scene
 Pattern Evidence—produced by direct contact between a
person and an object or between two objects
 Conditional Evidence—produced by a specific event or
action; important in crime scene reconstruction and in
determining the set of circumstances or sequence within a
particular event
 Transfer Evidence—produced by contact between person(s)
or object(s), or between person(s) and person(s)
 Associative Evidence—items that may associate a victim or
suspect with a scene or each other; ie, personal belongings
 DISCUSS WITH A NEIGHBOR AND COME UP WITH 2
EXAMPLES OF TRANSIENT, PATTERN, OR CONDITIONAL
EVIDENCE.
Examples of Transient Evidence
 Odor—putrefaction, perfume,
gasoline, urine, burning,
explosives, cigarette or cigar
smoke
 Temperature—surroundings,
car hood, coffee, water in a
bathtub, cadaver
 Imprints and indentations—
footprints, teeth marks in
perishable foods, tire marks
on certain surfaces
 Markings
Chapter 3
Examples of Pattern Evidence
Pattern Evidence—most are in the form of
imprints, indentations, striations, markings,
fractures or deposits.
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Blood spatter
Glass fracture
Fire burn pattern
Furniture position
Projectile trajectory
Tire marks or skid marks
 Clothing or article
distribution
 Gun powder residue
 Material damage
 Body position
 Tool marks
 Modus operandi
Examples of Conditional Evidence
 Light—headlight, lighting
conditions
 Smoke—color, direction of
travel, density, odor
 Fire—color and direction of
the flames, speed of spread,
temperature and condition of
fire
 Location—of injuries or
wounds, of bloodstains, of
the victim’s vehicle, of
weapons or cartridge cases,
of broken glass
 Vehicles—doors locked or
unlocked, windows opened
or closed, radio off or on
(station), odometer mileage
 Body—position, types of
wounds; rigor, livor and algor
mortis
 Scene—condition of
furniture, doors and
windows, any disturbance or
signs of a struggle
Classification of
Evidence by Nature
 Biological—blood, semen, saliva, sweat, tears, hair,
bone, tissues, urine, feces, animal material, insects,
bacterial, fungal, botanical
 Chemical—fibers, glass, soil, gunpowder, metal,
mineral, narcotics, drugs, paper, ink, cosmetics,
paint, plastic, lubricants, fertilizer
 Physical—fingerprints, footprints, shoe prints,
handwriting, firearms, tire marks, tool marks,
typewriting
 Miscellaneous—laundry marks, voice analysis,
polygraph, photography, stress evaluation,
psycholinguistic analysis, vehicle identification
Evidence Characteristics
 Class—common to a group of objects or persons
 Individual—can be identified with a particular
person or a single source
Fingerprints
Blood DNA Typing
Class vs Individual Evidence
Which examples do
you think could be
individual
evidence?
Chapter 3
COLLECTING AND
PACKAGING EVIDENCE
 One individual should be designated as the evidence
collector to ensure that the evidence is collected,
packaged, marked, sealed, and preserved in a consistent
manner
 Each item must be placed in a separate container, sealed,
and labeled
 Most fragile is collected and packaged first
 Different types of evidence require specific or special
collection and packaging techniques
 The body is the property of the coroner or medical
examiner. The collection of evidence on the body is done
by that department
PACKAGING
Most items should be packaged in a
primary container and then placed
inside a secondary one. These are
then placed inside other containers
such as paper bags, plastic bags,
canisters, packets and envelopes
depending on the type and size of
the evidence.
CHAIN OF CUSTODY
There must be a written record of all people
who have had possession of an item of
evidence.
 The evidence container must be marked for
identification
 The collector’s initials should be placed on the
seal
 If evidence is turned over to another person, the
transfer must be recorded.
Chapter 2 Vocabulary
Rough Sketch
A draft representation of all essential
information and measurements at a crime
scene. This sketch is drawn at the crime scene.
Finished Sketch
A precise rendering of the crime scene, usually
drawn to scale.
CORPUS DELICTI
“Body of the Crime”
 You must prove
 that a crime occurred
 that the person charged with the crime was responsible for the
crime
 Source of Evidence
 Body
 Primary and/or Secondary Crime Scene
 Suspect(s)
CRIME SCENE TEAM
 A group of professional investigators, each
trained in a variety of special disciplines.
 Team Members
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First Police Officer on the scene
Medics (if necessary)
Investigator(s)
Medical Examiner (if necessary)
Photographer and/or Field Evidence Technician
Lab Experts
CRIME SCENE
INVESTIGATION
Based on the scientific method and the
Locard Exchange Principle, logic and forensic
techniques
 Involves:
 Recognition—scene survey, documentation,
collection
 Identification—comparison testing
 Individualization—evaluation and interpretation
 Reconstruction—reporting and presenting
PROCESSING A
CRIME SCENE
 Isolate and secure the
scene
 Document the scene
 Search for evidence
 Collect and package
evidence, maintaining
the chain of custody
 Submit evidence to the
crime lab
FIRST OFFICER
ON THE SCENE
A
Assess the crime scene
and assist those hurt
D
Detain the witness
A
Arrest the perpetrator
P
Protect the crime scene
T
Take notes
CRIME SCENE SURVEY
Walk-through—performed by the crime scene investigator, the first officer
and sometimes the lead detective
Purpose:
 Mentally prepare a reconstruction theory
 Note any transient or conditional evidence that could change over
time.
 Note weather conditions
 Note points of entry or exit, as well as paths of travel within the crime
scene
 Record initial observations of who, what, where, when, and how
 Identify special needs within the crime scene for personnel,
precautions or equipment and notify superior officers or other
agencies
DOCUMENTATION
 Notes—date and time, description of the location, weather
and environmental conditions, description of the crime,
location of the evidence relative to other key points, the
names of all people involved, modifications that have
occurred and other relevant information
 Photography—photos of scene and surroundings, midrange to close-up photos with various angles of each
piece of evidence, photos as viewed by any witnesses.
 Sketches—inclusion of date, time, scale, reference
points, distance measurements, names of investigators,
victims, suspects, and a legend (key)
 Videography—allows narration (non-subjective) to be
included
CRIME SCENE SKETCH
Date: August 14, 2005
Time: 11:35 am
Criminalist: Ann Wilson
Location: 4358 Rockledge Dr, St. Louis, Mo.
N
Guest Speaker Questions
Sgt. Katherine Scheimreif from the CMPD will be
our guest speaker on September 16
Sgt. Scheimreif is the Unit Leader of the Crime
Scene Search team
Come up with 2 questions that you could ask her
based on what we have learned so far or that directly
relate to a crime scene
Chapter 1 Review
If your group is waiting to complete the lab then
you can work on the Chapter 1 Review questions,
#1-29 on pages 33-34
Recording a Crime Scene Lab
Read over the background information and
instructions of the lab so that your group will be
prepared when you enter the crime scene.
Determine who will be completing the following
tasks in your group:
Sketcher – complete the sketch
Photographer- take all photographs that are needed
Recorder – take measurements of crime scene and record
data in the data table
Manager (if extra person) – make sure group completes
all required parts; place numbered markers and help
others as needed
Recording a Crime Scene Lab
When you have left the crime scene, complete the
procedures for after the crime scene.
Be sure to work together as a team to complete the
sketch and to go through the photographs.