The effect of paint type on the development of latent fingermarks on walls

Abstract

Despite recent advances in DNA technology, fingermark evidence remains a fundamental method of ascertaining an individual's identity. Latent fingermarks are the commonest type of fingermark encountered at crime scenes. The Fingermark Visualisation Manual provides crime scene practitioner's with sequential information regarding which enhancement processes are best suited for a range of deposition surfaces (Bandey et al., 2014) [1]. However, there are still many surfaces, such as painted walls where more knowledge is required regarding which development techniques provide optimum results. In this study, four paint types were tested (matt, silk, bathroom and eggshell). Fingermarks were deposited on painted simulated walls and aged for 1 day, 1 week and 1 month. Fingermarks were developed by three processes highlighted as the most frequently used by practitioners (magnetic granular powder, magneta flake powder and ninhydrin). The results showed that overall black magnetic granular powder outperformed both magneta flake powder and ninhydrin on all paint types. This contradicts current UK guidelines for enhancement of fingermarks on matt painted walls, as black magnetic granular powder is not a recommended process at present. SEM and SEM-EDX analysis showed distinct differences between matt paint and the three non-matt paints tested, which provides an explanation for the results obtained.

Keywords: Fingermarks; Magnetic powders; Microscopy; Ninhydrin; Paint types.