The application of imaging technologies in the detection of trace evidence in forensic medical investigation

Abstract

LocardÕs Exchange Principle necessitates that the bodies of victims of crime be treated as secondary crime scenes. Imaging technologies should be implemented with a view towards discovering trace evidence that may aid subsequent investigations. In a country notorious for violent crime, it seems that South African medico-legal laboratories make minimal application of technology in the death investigation process and little attention is given to trace evidence. Non-destructive, non-invasive, portable and cost-effective tools are required. A torch, magnifying lamp, portable digital microscope and alternate light source were tested to gauge their potential for trace evidence detection on the bodies of victims of fatal interpersonal violence. Most studies apply these and similar tools to inert surfaces, with few focussing on their application to human skin. The most common evidence types discovered on the bodies and clothing of victims of fatal interpersonal violence, as well as the propensity of each tool to detect these, was evaluated in order to devise the best option for incorporation into the Pretoria Medico-Legal Laboratory routine. The study aimed to justify the investment of slightly more time, effort and funding into trace evidence recovery in the South African mortuary environment. It was also hoped that the application of these tools could be extended to the clinical forensic setting.