The Differentiation of Species and Fingermark Visualisation on Leathers
Fingermark uniqueness assists with the identification of individuals. The predominance of latent fingermarks at crime scenes highlights the paramount importance of their development and subsequent visualisation. Despite a plethora of techniques being available, the selection is dependent upon substrate surface texture, porosity, colour and exposure to varied environmental conditions. However, leather surfaces are typically challenging, despite their frequent occurrence in casework (vehicle interiors, footwear, clothing, wallets, restraints and weapons). Furthermore, the complexity of leathers continues in regards to sub-categorisation, including authenticity (faux, genuine), chemical process finishes (dyes, patent, pearlised, waterproofing), physical surface properties (embossed, smooth, textured) and source (fish, mammalian, reptile). Therefore, this presentation will focus on this varied group with regards to fingermark development and subsequent visualisation, by targeting reagent delivery mode, environment conditions for varied timeframes and sequential processing. Here we report investigations into such variations using two novel reagents (PolycyanoUV and FPNatural1) as advancements of conventional powdering and cyanoacrylate fuming application methods. In particular this work will detail an innovative powdery delivery style. Visualisation involved extension beyond the visible region of the electromagnetic spectrum in both directions (to the UV and IR) with different modes of interaction (excitation and emission). It will further explore the diversity of leather origin and in particular the differential histological surface and cross-sectional structures of bovine, caprine, cervine, ovine, porcine and more recently equine leather in both 2D and 3D, via high power digital microscopy and optical profiling. Further interesting observations include the apparent distinction from immature to mature animals within the same species. Ultimately, the practitioner recommendations will offer enhanced success rates on substrates previously deemed unsuitable. Additionally, the prospect of varied offence investigations (wildlife crime, acquisition, weapons, sexual assaults, homicide) encountering leather surfaces ensures that these results will interest multiple international jurisdictions in assisting propositions of the defence and prosecution.
Citation : Nichols-Drew, L. (2018) The Differentiation of Species and Fingermark Visualisation on Leathers. Australia and New Zealand Forensic Science Society 2018 Symposium in Perth, Australia
Peer Reviewed : Yes
- Leicester School of Pharmacy