Forensic footwear evidence can be used in legal proceedings to help prove that a shoe was at a crime scene. Footwear evidence is often the most abundant form of evidence at a crime scene and in some cases can prove to be as specific as a fingerprint. Initially investigators will look to identify the make and model of the shoe or trainer which made an impression. This can be done visually or by comparison with evidence in a database; both methods focus heavily on pattern recognition and brand or logo marks. Information about the footwear can be gained from the analysis of wear patterns which are dependent on angle of footfall and weight distribution. Detailed examination of footwear impressions can help to link a specific piece of footwear to a footwear imprint as each shoe will have unique characteristics.
Footwear evidence can come in at least three forms, footwear outsole impressions, footwear insole impressions and footwear trace evidence.
Footwear outsole impressions are impressions left on an object that was caused by contact with a piece of footwear. These can be left on the ground or raised surface by persons treading over it, left on doors or walls by persons attempting to kick or climb over a wall or even left on other persons after being kicked or stomped on.
There can also be latent impressions not easily visible to the naked eye, on many different surfaces such as floor tiles, concrete or even carpet. Detection may require the use of additional specialized light sources such as portable ultraviolet lighting. Recovery typically includes photography as well as lifting with "gel" or "electrostatic" dust lifters.
Imprints of a person's foot can be left on the insole's inside footwear. The size and arrangement of foot and toe imprints can be used to determine whether a person has worn a piece of footwear. The analysis and comparisons of foot imprints is part of the discipline of forensic podiatry.
Footwear trace evidence is trace evidence that is recovered from footwear. Types of trace evidence that could be recovered include skin, glass fragments, body hair, fibers from clothing or carpets, soil particles, dust and bodily fluids. The study of this trace evidence could be used to link a piece of footwear to a location or owner. DNA can be one of the contributing factors in forensic footwear evidence.
Footwear impressions can be detected with a variety of methods including: