Hide and seek: fingermark visualisation on leathers surfaces using novel reagents

Date

2017-10

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Conference

Peer reviewed

Yes

Abstract

The uniqueness of fingermarks is an integral component in the identification process of an individual. The predominance of latent crime scene marks requires subsequent development methodologies for visualisation. The appropriateness of the numerous techniques available is dependent upon the target surface characteristics, such as porosity and colour, with environmental exposure conditions. However, certain surfaces remain a problem for practitioners, especially when frequently encountered in casework, such as leather. Offences include: violent crime (weapon sheaths, holsters, restraints), wildlife investigations (skins, hides) and acquisitive crime (wallets, clothing). Therefore, the overall aim of this presentation is latent fingermark visualisation on leather surfaces.

Leather can be sub-categorised relating to source (fish, mammalian, reptile), authenticity (genuine or faux), physical surface properties (embossed, textured, smooth) and chemical finishes (dyes, waterproofing, patent, pearlised). Ultimately, such diversities may require an assortment of treatments optimum for fingermark development. Here we report investigations into such variations using two well-established application methods (powdering and cyanoacrylate fuming) associated with two novel reagents (PolycyanoUV and FPNatural1), whose observation is associated with opposite ends of the electromagnetic spectrum (UV and IR, respectively) and different modes of interaction (excitation and emission). Practically, the attraction of PolycyanoUV is its “one-step” application and of FPNatural1 is its potential for eradicating background interference.

This presentation explores latent fingermark visualisation on leather samples exposed to differing environmental conditions for varying time periods, in conjunction with reagent delivery mode and sequential treatment processing. These observations are supported by substrate microscopy in cross section and optical profiling in 2D and 3D. Further interesting insights include substantial variations in histological structure for bovine, caprine, cervine, ovine and porcine leathers, with the distinction leather from young and aged animals of the same species. The influence of these morphological differences on reagent efficacy will be discussed. Additionally, details will be included of a novel application method for FPNatural1.

These fundamental insights ultimately lead to enhanced success rates for visualisation of latent fingermarks on leather surfaces. These offer the prospect of outcomes that could assist in the investigation of many offence types and provide valuable forensic evidence on previously unusable substrates. Furthermore, the findings will have significant impact within international Criminal Justice Systems.

Description

Keywords

Suede Leather Visualisation Fingermark, PolycyanoUv FPNatural1 UV IR

Citation

Nichols-Drew, L.,Coulston, J. and Hillman, R. (2017) 'Hide and seek: fingermark visualisation on leathers surfaces using novel reagents.' International Association of Identification - European Division Conference, Amsterdam, Netherlands. 12-13 October.

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Research Institute

Leicester Institute for Pharmaceutical Innovation - From Molecules to Practice (LIPI)