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© 2017 Elsevier B.V. To support fingerprint expert opinion, this research proposes an approach that combines subjective human analysis (as currently applied by fingerprint practitioners) with a statistical test of the result. This approach relies on the hypothesis that there are limits to the distortion caused by skin stretch. Such limits can be modelled by applying a multivariate normal probability density function to the distances and angle formed by a marked ridge characteristic and the two closest neighbouring minutiae. This study presents a model tested on 5 donors in total. The “expected range” of distortion in a within-source comparison using 10 minutiae was determined and compared to between-source comparisons. The expected range of log probability densities for within-source comparisons marked with 10 minutiae was determined to be from −33.4 to −60.0, with all between-source data falling outside this range, between −83 and −305. These results suggest that the proposed generated metric could be a powerful tool for the assessment of fingerprint expert opinion in operational casework.

The detection and identification of volatile compounds is essential to the successful undertaking of numerous forensic analyses. Biological olfactory systems possess the extraordinary ability to not only detect many thousands of distinct volatile compounds (odors) but also to discriminate between them. Whole-organism biological sensors, such as detection canines, have been employed in forensic science as volatile compound detectors for many years. A variety of insects including bees, wasps, and moths, which have also been shown to detect volatile compounds of forensic significance, have been investigated for their potential application in field-based detection systems. While the fundamental aim for many developers of portable instruments is to replicate the remarkable ability of biological olfactory systems, such analytical equipment is yet to possess the detection and discriminatory powers achieved by biological sensors. Recent literature reveals an increasing interest in olfactory receptors - the biological components that impart olfactory ability - for detecting volatile compounds associated with forensically significant substances such as explosives and illicit drugs. This paper reviews the literature regarding the current, and potential future, use of biological organisms as sensors for forensic science applications. © 2013 Elsevier Ireland Ltd.

This paper describes the application of a luminescent lipid stain, nile red, for the development of latent fingermarks on porous surfaces. An optimised formulation is presented that provides rapid development of latent fingermarks on porous surfaces that are or have been wet. A comparison with physical developer (PD), the method of choice to enhance such fingermarks, indicated that nile red was a simpler and more stable technique for the development of fingermarks. The nile red formulation showed similar performance to PD across a range of substrates and ageing conditions, although PD still showed greater sensitivity on five-year-old examination booklets used in a pseudo-operational study. The pseudo-operational trial also indicated that nile red consistently developed different fingermarks to those enhanced by PD, suggesting that it preferentially targets a different fraction of the latent fingermark deposit. Significantly, the compatibility of nile red in a detection sequence with indanedione-zinc, ninhydrin and PD is reported. © 2013 Elsevier Ireland Ltd.

Conventional fingermark powders rely on contrast induced by absorption/reflection (e.g. black powder) or luminescence in the visible region (e.g. Blitz Green ®). In most cases, these powders provide sufficient contrast; however, in some circumstances surface characteristics can interfere with the visualisation of powdered fingermarks. Visualisation in the near infra-red (NIR) region, however, has been shown to eliminate interferences commonly encountered in the visible region. In this study, a mixture of rhodamine 6G and the NIR laser dye styryl 11 (STaR 11) was coated onto an aluminium oxide nanopowder and then mixed with silver magnetic powder to develop and visualise fingermarks in the NIR. When compared to Blitz Green ®, it was determined that the STaR 11 magnetic powder was better suited for marks deposited on textured surfaces and for older marks, whereas Blitz Green ® performed better on smooth glossy surfaces. The ability of the STaR 11 mixed dye formulation to be visualised in both the visible and NIR regions also provides a significant advantage over conventional luminescent fingermark powders. © 2012 Elsevier Ireland Ltd.

In current casework, most post-cyanoacrylate stains rely on luminescence emission in the visible region (400-700nm). While traditional stains such as rhodamine 6G work well under most circumstances, some surfaces may generate background luminescence under the same conditions. Detection in the near-infrared region (NIR>700nm) has shown to be effective in minimizing the interferences from such surfaces. The laser dye styryl 11 generated strongly luminescent fingermarks when applied after cyanoacrylate fuming on all surfaces tested. When compared to rhodamine 6G, the dye was superior only when viewed in the NIR. Styryl 11 was subsequently combined with rhodamine 6G, and the mixed stain formulation (named StaR 11 by the authors) induced stronger luminescence compared with styryl 11 alone with an ability to visualize in both the visible and NIR regions. Reliable and consistent results were obtained when using either styryl 11 alone or the STaR 11 mixture. The enhancement achieved did not otherwise vary depending on the source of the fingermark secretions. With visualization possible in both the visible and NIR regions, the styryl 11/rhodamine 6G mixture showed significant potential as a post-cyanoacrylate stain. © 2011 American Academy of Forensic Sciences.

Anecdotal evidence from forensic practitioners and studies conducted under controlled conditions have indicated that the reaction between 1,2-indanedione and the amino acids present in latent fingermark deposits is highly susceptible to ambient humidity. The addition of catalytic amounts of zinc chloride to the 1,2-indanedione working solution - usually in the order of 1:25 to 1:4 molar ratio (indanedione:zinc) - significantly improves the colour and luminescence of fingermarks treated under dry conditions but appears to have a negligible effect on fingermarks treated in humid environments. The results presented in this paper confirmed that zinc(II) ions added to the 1,2-indanedione working solution act as a Lewis acid catalyst, stabilising a key intermediate during a rate-limiting hydrolysis step. Furthermore, studying the reaction using a chromatography-grade cellulose substrate method previously reported confirmed that cellulose substrates play a major role in facilitating the indanedione-amino acid reaction by acting as a surface catalyst in the early stages of the reaction and by directing the formation of the desired luminescent product (Joullié's Pink). © 2011 Elsevier Ireland Ltd.

Cyanoacrylate fuming is one of the most common techniques employed for the detection of latent fingermarks on non-porous surfaces such as plastic and glass. The technique is generally applied by exposing items of interest to the vapours generated by heating a suitable quantity of commercial cyanoacrylate adhesive. In this study, the potential for highly toxic hydrogen cyanide (HCN) to be generated from the overheating of cyanoacrylate was investigated. Two commercial cyanoacrylate adhesives and two quantitative methods for the determination of HCN were employed: (i) the sodium picrate method; and (ii) the picrate-resorcinol method. 13C nuclear magnetic resonance (NMR) analysis was used to confirm the presence of cyanide. In addition, the thermal decomposition of cyanoacrylate was studied using simultaneous thermogravimetric and differential thermal analysis (TGA-DTA). It was determined that detectable and quantifiable amounts of HCN were generated from the thermal decomposition of cyanoacrylate monomer and polymer at temperatures as low as 200°C. Using an optimised picrate-resorcinol method, it was shown that around 10μg of HCN could be generated from the heating of 1g of cyanoacrylate monomer at 200°C. For one of the adhesives tested, this increased to above 100μg of HCN when 1g of cyanoacrylate monomer was heated at 280°C. Recommendations are provided that, if followed, should ensure that the cyanoacrylate fuming process can be safely applied with minimal risk to the operator. © 2011 Elsevier Ireland Ltd.

Enantioselective anti-l-amino acid antibodies conjugated to gold nanoparticles are shown to facilitate the detection of latent fingermarks by interacting with amino acids present in friction ridge secretions. This antibody-based system is particularly effective for the enhancement of aged and dried fingermarks on non-porous surfaces, an area unexploited by current techniques. © 2011 The Royal Society of Chemistry.

Continual reports of illicit trafficking incidents involving radioactive materials have prompted authorities to consider the likelihood of forensic evidence being exposed to radiation. In this study, we investigated the ability to recover latent fingermark evidence from a variety of substrates that were exposed to ionizing radiation. Fingermarks deposited on common surfaces, including aluminum, glass, office paper, and plastic, were exposed to doses ranging from 1 to 1000 kGy, in an effort to simulate realistic situations where evidence is exposed to significant doses of radiation from sources used in a criminal act. The fingermarks were processed using routine fingermark detection techniques. With the exception of glass and aluminum substrates, radiolysis had a considerable effect on the quality of the developed fingermarks. The damage to ridge characteristics can, in part, be attributed to chemical interactions between the substrate and the components of the fingermark secretions that react with the detection reagents. © 2009 American Academy of Forensic Sciences.

A new, highly fluorescent dye was synthesised using oleylamine combined with a perylene dianhydride compound. The new dye was characterised by 1H NMR, UV-vis spectroscopy and fluorescence spectroscopy as well as quantum yield. The dye was absorbed onto titanium dioxide nanoparticles for use as a fingerprint detection powder. The new fluorescent powder was applied to latent fingermarks deposited onto different non-porous surfaces and compared with commercial fluorescent powders. The powder exhibits strong fluorescence at 650-700 nm under excitation at 505 nm. On glass surfaces, the new powder gave images showing tertiary-level detail of the fingermark ridges with almost no background development. Compared with current magnetic fluorescent powders, the new powder was slightly weaker in fluorescence intensity but produced significantly less background development, resulting in good contrast between the fingermark and the substrate. © 2007 Elsevier Ireland Ltd. All rights reserved.

The key role of a forensic scientist is to assist in determining whether a crime has been committed, and if so, assist in the identification of the offender. Many people hold the belief that a particular item can be conclusively linked to a specific person, place or object. Unfortunately, this is often not achievable in forensic science. In performing their role, scientists develop and test hypotheses. The significance of those hypotheses that cannot be rejected upon completion of all available examinations/analyses is then evaluated. Although one can generally identify the substances present using available techniques, it is generally not possible to distinguish one source of the same substance from another. In such circumstances, although a particular hypothesis cannot be rejected, it cannot be conclusively proven, i.e. the samples could still have originated from different sources. This limitation of not being able to distinguish between sources currently extends to the analysis of other forensic samples including, but not limited to, ignitable liquids, paints, adhesives, textile fibres, plastics, and illicit drugs. Stable isotope ratio mass spectrometry (IRMS) is an additional technique that can be utilised to test a given hypothesis. This technique shows the potential to be able to individualise a range of materials of forensic interest. This paper provides a brief description of the technique, followed by a review of the various applications of IRMS in different scientific fields. The focus of this summary is on forensic applications of IRMS, in particular the analysis of explosives, ignitable liquids and illicit drugs. © 2005 Elsevier Ireland Ltd. All rights reserved.