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The Latent Print Unit
conducts all work pertaining to the examination of latent prints
on evidence submitted to the FBI Laboratory. Latent prints are
impressions produced by the ridged skin on human fingers, palms,
and soles of the feet. Unit examiners analyze and compare latent
prints to known prints of individuals in an effort to make identifications
or exclusions. The uniqueness, permanence, and arrangement of
the friction ridges allow Unit examiners to positively match
two prints and to determine whether an area of a friction ridge
impression originated from one source to the exclusion of all
others.
A variety of techniques,
including use of chemicals, powders, lasers, alternate light
sources, and other physical means, are employed in the detection
and development of latent prints. In instances where a latent
print has limited quality and quantity of detail, Unit personnel
may perform microscopic examinations in order to effect conclusive
comparisons.
In 1999 the FBI developed
and implemented a new automated fingerprint system known as the
Integrated Automated Fingerprint Identification System (IAFIS).
Although IAFIS is primarily a ten-print system for searching
an individual's fingerprints to determine whether a prior arrest
record exists and then maintaining a criminal arrest record history
for each individual, the system also offers significant latent
print capabilities. Using IAFIS, a latent print
specialist can digitally capture latent print and ten-print images
and perform several functions with each. These include:
- Enhancement to improve
image quality;
- Comparison of latent
fingerprints against suspect ten-print records retrieved from
the criminal fingerprint repository;
- Searches of latent
fingerprints against the ten-print fingerprint repository when
no suspects have been developed;
- Automatic searches
of new arrest ten-print records against an unsolved latent fingerprint
repository; and
- Creation of special
files of ten-print records in support of major criminal investigations.
Using the IAFIS fingerprint
search capability against data from the FBI Criminal Justice
Information Services (CJIS) Division, which maintains the world's
largest repository of fingerprint records, the Unit has made
identifications in cases for which no known suspects were named
for comparison purposes and in cases in which latent prints on
crime scene-related evidence were not identified with suspects
named in the investigation.
Personnel from the
Latent Print Unit also form the nucleus of the FBI Disaster Squad,
which renders assistance in identifying victims at disaster scenes.
This squad may be deployed upon official request from the ranking
law enforcement official at the scene, the medical examiner or
coroner in charge of victim identification, the ranking official
of a public transportation carrier, the National Transportation
Safety Board, the Federal Aviation Administration, or the U.
S. Department of State in instances of foreign disasters involving
U. S. citizens. Since 1940, the Disaster Squad has responded
to over 200 disasters worldwide and has identified over half
of the victims by fingerprints or footprints.
Unit personnel use
special techniques in the examination of fingers and hands of
unknown deceased individuals to obtain identifiable prints. Automated
searches of identifiable prints can be conducted in the IAFIS
database, which contains over 36 million individuals' known fingerprints.
If classifiable prints are obtained from all ten fingers, manual
searches can also be conducted in the CJIS civil fingerprint
file.
The Unit also provides
training in all aspects of latent print work to local, state,
federal, and foreign law enforcement personnel. In addition,
the Unit conducts research to evaluate new technologies, procedures,
and equipment.
Occasionally, in matters
initiated by entities outside the FBI, the Unit will serve as
a final authority when the authenticity, value, and/or identification
of friction ridge impressions is questioned or challenged.
For more information
about latent print evidence or the Latent Print Unit, see the
Latent
Print Examinations
section of the Handbook
of Forensic Services.
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