When public security agencies conduct crimescene investigations, they place great importance on evidence, especially the collection of physical evidence such as fingerprints and shoeprints. In recent years, the role of shoeprint evidence in solving cases has become increasingly significant. So, what is the scientific basis of shoeprint evidence investigation?
A shoeprint is a mark left by a person's footor shoe, sock, etc., on the ground or another supporting surface while standing or walking. Shoeprints are a crucial type of physical evidence frequently used in criminal investigations. In modern criminal proceedings, shoeprints, like fingerprints, tool marks, and ballistic evidence, are among the important pieces of evidence. While fingerprints have the established status of being the “Evidence King”, the scientific discussion about the validity of fingerprint identification has brought the specificity of shoeprint identification to the forefront. Moreover, due to its inherent characteristics, shoeprints areplaying an increasingly important role in the process of case investigation.
Figure 1. Analyze and compare shoeprints
Specificity of shoeprints. Both the visual features and walking patterns displayed by shoeprints exhibit a certain specificity. The visual features refer to the structural characteristics reflecting the appearance of bare feet, shoes, or socks of a single shoeprint. The walking pattern features of shoeprints reflect the characteristics of a single or a series of shoeprints, revealing the regularities in a person's walking habits. These characteristics, influenced by factors such as gender, age, height, weight, occupation, and walking posture, differ for each individual.
Figure 2. Gait
Relative stability of shoeprints. The structural forms of feet, shoes, and socks, as well as the walking movement patterns, undergo changes over time, but throughout this long-term process of change, they always maintain their inherent basic features.
Figure 3. Footprint pressure comparison for the same person
Reflectivity of shoeprints. The continuity of shoeprints reflects the movement patterns of feet and can be used to analyze the process of a criminal suspect engaging in criminal activities and track shoeprints continuously. Shoeprints not only reflect the structural forms of bare feet, shoes, or socks but also reflect their movement patterns. The reflectivity of shoeprints provides a material foundation for shoeprint analysis and identification. Research has shown that by analyzing eight shoeprints from an individual, one can obtain data on their height, gender, weight, and other characteristics, with an accuracy comparable to fingerprint identification.
Figure 4. Footwear impressions analysis of personal information
Continuity of shoeprints. The continuity of shoeprints reflects the movement patterns of feet and can be used to analyze the process of a criminal suspect engaging in criminal activities and track shoeprints continuously.
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