Forensic evidence consists of all the physical objects that can be observed by the ﬁve human senses and analyzed regarding their relevance to the events that occurred at a crime scene. Any physical item can be a source of information that assists the investigator in reconstructing the sequence of occurrences. A line of evidence that can establish a time frame for the presence of an individual is the interpretation of footwear impression evidence.
Footprints (or footmarks) are the impressions or images left behind by a person walking or running. The print left behind at a crime scene can give vital evidence to the perpetrator of the crime. Shoes have many different prints based on the sole design and the wear that it has received – this can help to identify suspects. Photographs or castings of footprints can be taken to preserve the finding. Analysis of footprints and shoe prints is a specialist part of Forensic Science.
Footprints can also allow the detective to find the approximate height from footprint and shoeprint. The Foot tends to be approximately 15% of the person’s average height. Individualistic characteristics of the footprints like numerous creases, flatfoot character, horizontal and vertical ridges, corns, deformities etc. can help the forensic scientist in cases pertaining to criminal identification. In some forensic cases, the need may also arise to estimate body weight from the size of the footprints.
Footprints may be found as either two dimensional prints or three dimensional impressions. Prints are made by depositing (blood, soil) or removing (dust, blood) material from a hard surface. Impressions are made in a pliable material such as mud, sand or snow. Footprints can represent both class and individual trace evidence. A shoe print can be unique because of many variables: wear patterns can show how long it was worn and sometimes the walking pattern of the shoe’s owner. Some marks, cuts and scratches are unique to a particular shoe. Even a rock stuck in the treads of an athletic shoe can remain and leave a unique characteristic. The design of the sole is a class characteristic as is the size. However, some types of shoe are sold in limited quantities in certain sizes. Photography is the major technique used to record shoe prints and tracks. It can be enhanced with chemicals, and is often combined with casting for impressions.