The recoverability of fingerprints on paper exposed to elevated temperatures - Part 1: comparison of enhancement techniques

Dominick, Ainsley J. and NicDaeid, N. and Bleay, Stephen M., Home Office Scientific Development Branch, Sandridge, UK (2010) The recoverability of fingerprints on paper exposed to elevated temperatures - Part 1: comparison of enhancement techniques. Journal of Forensic Identification, 59 (3). pp. 325-339. ISSN 0895-173X

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Abstract

This research investigates the recoverability of fingerprints which have been exposed to elevated temperatures in order to mimic the environment a piece of paper may be exposed to within an arson scene. Arson is an expensive crime, costing the UK economy, on average, £53.8 million each week [1]. Anything which may give rise to the identity of the fire setter should be analysed and as such, unburnt paper may be a potential source of fingerprints. While it is true that even a moderate fire will obscure and render partially useless some types of evidence, many items, including fingerprints, may still survive [2-4]. This research has shown that fingerprints are still retrievable from paper which has been subjected to the maximum testing conditions of 200˚C for 320min. In fact, some fingerprints naturally enhance themselves by the heating process. This investigation has also shown that the most effective enhancement technique was found to be 1,8-diazafluoren-9-one (DFO) for exposure temperatures upto 100˚C. Physical developer (PD) is the most effective enhancement technique for exposure temperatures from 100˚C to 200˚C. For porous surfaces, there are fingerprint development techniques which are effective at enhancing fingerprints exposed upto a temperature of 200˚C, irrespective of the firefighting extinguishing technique, as PD, in addition to developing fingerprints exposed to high temperatures, is one of the few processes which will enhance fingermarks on wetted surfaces.