DETECTION OF FIREARMS IMPRINTS ON HANDS OF SUSPECTS - STUDY OF THE PDT-BASED FIELD-TEST

The results of a multifaceted research project towards the optimizatio n of the visualization process of firearms contact marks on hands are reported. Latent imprints that are formed by the close contact between the metallic parts of the weapons and the palms were visualized by th e application of the PDT iron (TL) reagent. Various factors affecting the quality of the marks were studied. Also PDT analogues were synthes ized and their performance compared with that of the original compound . Some of the analogues show slight advantages over PDT in contrast an d sensitivity, but PDT in acetone solution, such as in the commercial preparations Ferroprint or Ferrotrace seems to be the formulation of c hoice for reasons of availability and cost. It can visualize latent fi rearms impressions on the hands several hours after the contact.