U.S. Department of Justice, Office of Justice ProgramsNational Institute of JusticeThe Research,
Development, and Evaluation Agency of the U.S. Department of Justice
Glossary
The definitions contained herein apply to terms as used in this
document.
ABFO scales
(American Board of Forensic Odontology scales). An L-shaped piece of
plastic used in photography that is marked with circles, black and white bars,
and 18-percent gray bars to assist in distortion compensation and provide
exposure determination. For measurement, the plastic piece is marked in
millimeters.
Alternate light source
Equipment used to produce visible and invisible light at various
wavelengths to enhance or visualize potential items of evidence (fluids,
fingerprints, clothing fibers, etc.).
Bindle paper
Clean paper folded to use to contain trace evidence, sometimes included as
part of the packaging for collecting trace evidence.
Biohazard bag
A container for materials that have been exposed to blood or other
biological fluids and have the potential to be contaminated with hepatitis,
AIDS, or other viruses.
Biological fluids
Fluids that have human or animal origin, most commonly encountered at
crime scenes (e.g., blood, mucus, perspiration, saliva, semen, vaginal fluid,
urine).
Biological weapon
Biological agents used to threaten human life (e.g., anthrax, smallpox, or
any infectious disease).
Bloodborne pathogen
Infectious, disease-causing microorganisms that may be found or
transported in biological fluids.
Boundaries
The perimeter or border surrounding potential physical evidence related to
the crime.
Case file
The collection of documents comprising information concerning a particular
investigation. (This collection may be kept in case jackets, file folders,
ring binders, boxes, file drawers, file cabinets, or rooms. Sub-files are
often used within case files to segregate and group interviews, media
coverage, laboratory requests and reports, evidence documentation,
photographs, videotapes, audiotapes, and other documents.)
Case identifiers
The alphabetic and/or numeric characters assigned to identify a particular
case.
Chain of custody
A process used to maintain and document the chronological history of the
evidence. (Documents should include name or initials of the individual
collecting the evidence, each person or entity subsequently having custody of
it, dates the items were collected or transferred, agency and case number,
victim's or suspect's name, and a brief description of the item.)
Chemical enhancement
The use of chemicals that react with specific types of evidence (e.g.,
blood, semen, lead, fingerprints) in order to aid in the detection and/or
documentation of evidence that may be difficult to see.
Chemical threat
Compounds that may pose bodily harm if touched, ingested, inhaled, or
ignited. These compounds may be encountered at a clandestine laboratory, or
through a homemade bomb or tankard leakage (e.g., ether, alcohol,
nitroglycerin, ammonium sulfate, red phosphorus, cleaning supplies, gasoline,
or unlabeled chemicals).
Clean/sanitize
The process of removing biological and/or chemical contaminants from tools
and/or equipment (e.g., using a mixture of 10-percent household bleach and
water).
Collect/collection
The process of detecting, documenting, or retaining physical evidence.
Comparison samples
A generic term used to describe physical material/ evidence discovered at
crime scenes that may be compared with samples from persons, tools, and
physical locations. Comparison samples may be from either an
unknown/questioned or a known
source.
Samples whose source is unknown/questioned are
of three basic types:
1. Recovered crime scene samples whose source is in
question (e.g., evidence left by suspects, victims).
2. Questioned evidence
that may have been transferred to an offender during the commission of the
crime and taken away by him or her. Such questioned evidence can be compared
with evidence of a known source and can thereby be associated/linked to a
person/ vehicle/tool of a crime.
3. Evidence of an unknown/questioned
source recovered from several crime scenes may also be used to associate
multiple offenses that were committed by the same person and/or with the same
tool or weapon.
Samples whose source is known are of
three basic types:
1. A standard/reference sample is
material of a verifiable/documented source which, when compared with evidence
of an unknown source, shows an association or linkage between an offender,
crime scene, and/or victim (e.g., a carpet cutting taken from a location
suspected as the point of transfer for comparison with the fibers recovered
from the suspect's shoes, a sample of paint removed from a suspect vehicle to
be compared with paint found on a victim's vehicle following an accident, or a
sample of the suspect's and/or victim's blood submitted for comparison with a
bloodstained shirt recovered as evidence).
2. A
control/blank sample is material of a known source that
presumably was uncontaminated during the commission of the crime (e.g., a
sample to be used in laboratory testing to ensure that the surface on which
the sample is deposited does not interfere with testing. For example, when a
bloodstain is collected from a carpet, a segment of unstained carpet must be
collected for use as a blank or elimination sample). 3. An
elimination sample is one of known source taken from a person
who had lawful access to the scene (e.g., fingerprints from occupants, tire
tread impressions from police vehicles, footwear impressions from emergency
medical personnel) to be used for comparison with evidence of the same type.
Contamination
The unwanted transfer of material from another source to a piece of
physical evidence.
Control/blank sample
See comparison samples.
Cross-contamination
The unwanted transfer of material between two or more sources of physical
evidence.
Documentation
Written notes, audio/videotapes, printed forms, sketches and/or
photographs that form a detailed record of the scene, evidence recovered, and
actions taken during the search of the crime scene.
Dying declaration
Statements made by a person who believes he or she is about to die,
concerning the cause or circumstance surrounding his or her impending death.
Elimination sample
See comparison samples.
Evidence identifiers
Tape, labels, containers, and string tags used to identify the evidence,
the person collecting the evidence, the date the evidence was gathered, basic
criminal offense information, and a brief description of the pertinent
evidence.
First responder(s)
The initial responding law enforcement officer(s) and/or other public
safety official(s) or service provider(s) arriving at the scene prior to the
arrival of the investigator(s) in charge.
Impression evidence
Objects or materials that have retained the characteristics of other
objects that have been physically pressed against them.
Initial responding officer(s)
The first law enforcement officer(s) to arrive at the scene.
Investigator(s) in charge
The official(s) responsible for the crime scene investigation.
Known
See comparison samples.
Latent print
A print impression not readily visible, made by contact of the hands or
feet with a surface resulting in the transfer of materials from the skin to
that surface.
Measurement scale
An object showing standard units of length (e.g., ruler) used in
photographic documentation of an item of evidence.
Multiple scenes
Two or more physical locations of evidence associated with a crime (e.g.,
in a crime of personal violence, evidence may be found at the location of the
assault and also on the person and clothing of the victim/assailant, the
victim's/assailant's vehicle, and locations the victim/assailant frequents and
resides).
Nonporous container
Packaging through which liquids or vapors cannot pass (e.g., glass jars or
metal cans).
Other responders
Individuals who are involved in an aspect of the crime scene, such as
perimeter security, traffic control, media management, scene processing, and
technical support, as well as prosecutors, medical personnel, medical
examiners, coroners, forensic examiners, evidence technicians, and fire and
rescue officers.
Personal protective equipment (PPE)
Articles such as disposable gloves, masks, and eye protection that are
utilized to provide a barrier to keep biological or chemical hazards from
contacting the skin, eyes, and mucous membranes and to avoid contamination of
the crime scene.
Porous container
Packaging through which liquids or vapors may pass (e.g., paper bags,
cloth bags).
Presumptive test
A nonconfirmatory test used to screen for the presence of a substance.
Projectile trajectory analysis
The method for determining the path of a high-speed object through space
(e.g., a bullet emanating from a firearm).
Radiological threat
The pending exposure to radiation energy. (This energy can be produced by
shortwave x-rays or through unstable isotopes.)
Single-use equipment
Items that will be used only once to collect evidence, such as biological
samples, then discarded to minimize contamination (e.g., tweezers, scalpel
blades, droppers).
Standard/reference sample
See comparison samples.
Team members
Individuals who are called to the scene to assist in investigation or
processing of the scene (e.g., scientific personnel from the crime laboratory
or medical examiner's office, other forensic specialists, photographers, mass
disaster specialists, experts in the identification of human remains, arson
and explosives investigators, clandestine drug laboratory investigators, as
well as other experts).
Trace evidence
Physical evidence that results from the transfer of small quantities of
materials (e.g., hair, textile fibers, paint chips, glass fragments, gunshot
residue particles).
Transient evidence
Evidence which by its very nature or the conditions at the scene will lose
its evidentiary value if not preserved and protected (e.g., blood in the
rain).
Unknown/questioned
See comparison samples.
Walk-through
An initial assessment conducted by carefully walking through the scene to
evaluate the situation, recognize potential evidence, and determine resources
required. Also, a final survey conducted to ensure the scene has been
effectively and completely processed.