For decades, fingerprints have provided investigators
invaluable clues to establish the identity of criminals. Yet,
another type of print impression that could be just as valuable
has been widely overlooked. Latent shoe prints exist in almost
all interior crime scenes but are often ignored by investigators
or destroyed by initial responders before the prints could be
processed.
Latent shoe prints are impressions of shoe treads left by an
individual on a surface. While these prints cannot be seen by
the naked eye, they can be revealed using standard fingerprint
powders. Although investigators routinely search for visible
shoe prints on interior surfaces and shoe impressions in
exterior crime scenes, they often overlook the existence of
latent shoe prints.
Like fingerprints, latent shoe prints can be used to place a
suspect at a crime scene. Though each shoe manufacturer produces
hundreds of various styles of footwear with the same tread
design, these identical prints quickly become unique through the
owner's use. Wear will vary depending on individual walking
styles and contact with different surfaces. Any scratch, nick or
cut will result in points of comparison, making the shoe ``one of
a kind.''
Most casual shoes have rubberized soles that, when exposed
to light amounts of moisture, react in a way similar to a finger
leaving its mark on a surface. Vinyl linoleum, smooth tile, and
painted floors provide the best surfaces for recovery of latent
shoe prints.
Many of the same factors that are involved in lifting
fingerprints are to be considered in recovering latent shoe
prints. The surface must be smooth enough to reveal the
characteristics of the soles. Temperature and weather conditions
must be conducive to preservation of the impressions. And, like
fingerprints, latent shoe prints are fragile and can be damaged
if further contact is made after the print is placed. They can
be easily altered or destroyed by first responders and curious
bystanders; therefore, it is important to carefully secure the
crime scene if recovery of the prints is to be successful.
Latent shoe prints have not been widely used in crime scene
investigations. Although recovery of the prints depends on
several unpredictable variables, they may yield valuable
information and, therefore, should be considered a viable option
for investigators.
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Information for this column was provided by Dwain A.
Pierce, Criminalistics Specialist, Police Department, Knoxville,
Tennessee.
