Posted in Forensics on 21. Mar, 2010
The definitions herein apply to the terms used in the document: “Crime Scene Investigation: A Guide for Law Enforcement” (NCJ 178280).
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
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
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
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
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).