PHYSICAL EVIDENCE MANUAL - Crime Scene Investigator Network

Physical Evidence Manual
10.0 FINGERPRINTS (FRICTION RIDGE SKIN)
EVIDENCE
Fingerprints (friction ridge skin) are a widely recognized means of personal
identification and their individuality and permanence make friction ridge skin
identification one of the most valuable forms of evidence. Most crime scene
evidence has the potential to reveal identifiable latent print impressions so
assume that latent prints are present on all objects handled by the perpetrator
and process or collect these pieces of evidence accordingly.
By examining the evidence submitted, the laboratory will be able to:
• Determine the presence of latent, patent or plastic print impressions.
• Determine if these print impressions are identifiable.
• Compare and identify these print impressions with the known friction ridge
print impressions of suspects and those of others for elimination purposes.
• Search for a possible latent donor by utilizing the Automated Fingerprint
Identification System (AFIS) to establish a list of potential candidates.
The Latent Print Laboratories are currently located in Bend, Central Point,
Portland Metro, and Springfield.
Collection, Packaging, and Submission of Evidence
Evidence collected from the crime scene for latent examination should be
submitted as an analytical case using the Forensic Services Request (Form 49).
Exhibits being forwarded to a laboratory should be initialed and dated when
practical. Take care, however, when marking the items that these marks are not
placed in an area which would likely obliterate any latent prints present. If
insufficient space exists for initialing, place the item in a bag, seal and properly
mark the exterior. The item should be packaged so that no rubbing action occurs
as this may destroy latent fingerprints present on the object.
Evidence should be submitted for examination as soon as possible after its
discovery. Exposure to water or dampness should be avoided. However, this
exposure does not necessarily destroy all latent prints. Any wet or damp object
must be air-dried before it is packed for shipment. Unless absolutely necessary,
do not process items of evidence which are to be submitted for latent prints. If
items have been processed prior to submission to a laboratory, package those
items to prevent smudging of the latent prints or possible breakage. All chemical
processing of items should only be done by trained latent examiner or technician
in the laboratory setting.
Identify all evidence, whether an original article, a lift, photographic negative or
image CD/DVD with a tag or a mark placed so it will not interfere with the latent
Adopted: May 2002
10-4
Revisions: 6
Last Revision: January 31, 2008