Volatilised pyrene: A phase 1 study demonstrating a new method of visualising fingermarks with comparisons to iodine...

Pyrene is a fluorescent polycyclic aromatic hydrocarbon that can be volatilised under mild conditions. When fumed, pyrene is rapidly absorbed into the sebaceous residues of fingermarks, enabling their fluorescent visualisation upon excitation with ultraviolet radiation. This new means of fluorescent fingermark detection is more sensitive than the non-fluorescent iodine fuming approach for nonporous surfaces. This is demonstrated here in a phase 1 study using split-print comparisons on metal and glass surfaces. Pyrene-treated fingermarks also retain the volatile fluorophore for comparably long time periods relative to iodine fuming (in the order of hours). The phase 1 study comprised four donors, and 80 natural fingermarks that were grouped into two time periods; aged 24h and 1 week. Iodine fuming was chosen as a reference to showcase the effectiveness of pyrene given it is the most closely-related chemical fuming method in routine use. This study demonstrates that pyrene fuming increases the quantity and quality of fingermark visualisations relative to iodine fuming, and is free of many of the latter method's drawbacks. Preliminary results shown here also show the effectiveness of pyrene fuming on highly patterned surfaces, and its compatibility with the use of gelatine lifters. Pyrene fuming is thus easy to effect, low-cost, and shows great promise as a new means of visualising fingermarks on non-porous surfaces.