Detection of firearm imprints on the hands of suspects: Effectiveness of PDT reaction

Pyridyldiphenyl triazine (PDT) and three of its analogues were compared as practical reagents for visualizing unseen impressions left on the hands of a person who has held a firearm. The parent compound, PDT, gave the best re sults using intensity and clarity as measuring criteria. The effectiveness of the PDT reaction was then studied on 147 volunteers who, had held firear ms in their hands. Identifiable impressions of the metallic parts of the we apons were developed on the hands of 103 volunteers (70%). Results with fem ales were slightly higher than with mates, however., the difference was pos sibly statistically insignificant, and needs further study, Ferroprint (TM) and Ferrotrace (TM),(5) commercial preparations that are based on the PDT reaction, have become a part of the professional equipment of every crime s cene technician in Israel.