Focus on Forensics: Latent Shoeprint Analysis

by Dwain A. Pierce

FOCUS ON FORENSICS: LATENT SHOEPRINT ANALYSIS

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. ____________

Information for this column was provided by Dwain A. Pierce, Criminalistics Specialist, Police Department, Knoxville, Tennessee.