PHYSICAL EVIDENCE MANUAL - Crime Scene Investigator Network

Physical Evidence Manual
Adopted: May 2002
Revisions: 6
Last Revision: January 31, 2008
9.0 FIBER EVIDENCE
Fibers are easily transferred between individuals and between individuals and
environments. Fiber evidence can be of value in cases such as homicides,
assaults, robberies, and burglaries. Research has shown that with few
exceptions the largest quantity of fibers on an object is from the last person to be
in contact with it. Therefore, it is advantageous to consider collecting fiber
evidence prior to processing for other types of evidence. Caution should be used
to prevent cross contamination of evidence collected for fiber examinations,
particularly when crime scene personnel will also be responsible for collecting
suspect or victim clothing items or for the processing of related scenes or
vehicles.
Laboratory analysts examine various physical, chemical, and microscopic
properties of fibers when performing a comparison between evidence fibers and
a potential source. Common conclusions include statements regarding the
similarity or dissimilarity of the evidence fiber(s) to the possible source or
standard. Fiber comparisons cannot, however, determine the source to the
exclusion of all others.
Fiber Examinations
The following may be determined from fiber examinations:
• The type of fiber (e.g. natural or synthetic, animal fiber, glass fiber, etc.)
• The possible product uses for the fiber (e.g. carpet fiber, clothing fiber,
etc.)
• The degree of similarity between evidence fiber(s) and a fiber source
Collection of Fiber Evidence
Fiber evidence can be collected in a number of ways. Table 4 lists various
methods and when they are appropriate.
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