Use of footwear impressions in crime scene investigations assisted by computerised footwear collection system

Crime scene footwear classification systems can be utilized to look for possible suspects, to get models and brand names for crime scene impressions and to link crime scenes. In this work a computerised footwear classification system is presented. The classification coding of the system has been designed especially for partial footwear impressions which are the most typical in crime scenes. The system is flexible because it is possible to agree within a crime scene investigation unit the way in which the system is to be applied. If outsole patterns are classified accurately in processing for the database, time will be saved in the search process and vice versa. The accurate classification coding is propounded by the fact that only a few experienced users are needed to perform the classification and data storage and all police officers returning from crime scenes are able to perform searches very easily. The users only have to follow the defined rules for geometric shapes. The crime scene investigation unit of the Turku police tested the system for a period of 1.5 years. The system has proved to be of valuable assistance in investigation when several of the hints lead to early solving of a crime. Practical experiences are described.