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Girod A.,University of Lausanne | Ramotowski R.,United States Secret Service | Lambrechts S.,University of Amsterdam | Misrielal P.,University of Amsterdam | And 2 more authors.
Forensic Science International | Year: 2016

The question of the age of fingermarks is often raised in investigations and trials when suspects admit that they have left their fingermarks at a crime scene but allege that the contact occurred at a different time than the crime and for legal reasons. In the first part of this review article, examples from American appellate court cases will be used to demonstrate that there is a lack of consensus among American courts regarding the admissibility and weight of testimony from expert witnesses who provide opinions about the age of fingermarks. Of course, these issues are not only encountered in America but have also been reported elsewhere, for example in Europe. The disparity in the way fingermark dating cases were managed in these examples is probably due to the fact that no methodology has been validated and accepted by the forensic science community so far. The second part of this review article summarizes the studies reported on fingermark dating in the literature and highlights the fact that most proposed methodologies still suffer from limitations preventing their use in practice. Nevertheless, several approaches based on the evolution of aging parameters detected in fingermark residue over time appear to show promise for the fingermark dating field. Based on these approaches, the definition of a formal methodological framework for fingermark dating cases is proposed in order to produce relevant temporal information. This framework identifies which type of information could and should be obtained about fingermark aging and what developments are still required to scientifically address dating issues. © 2016 Elsevier Ireland Ltd.

Shen W.,Lincoln Laboratory | Campbell J.,Lincoln Laboratory | Straub D.,Lincoln Laboratory | Schwartz R.,United States Secret Service
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2011

In this paper we attempt to quantify the ability of naive listeners to perform speaker recognition in the context of the NIST evaluation task. We describe our protocol: a series of listening experiments using large numbers of naive listeners (432) on Amazon's Mechanical Turk that attempts to measure the ability of the average human listener to perform speaker recognition. Our goal was to compare the performance of the average human listener to both forensic experts and state-of-the-art automatic systems. We show that naive listeners vary substantially in their performance, but that an aggregation of listener responses can achieve performance similar to that of expert forensic examiners. © 2011 IEEE.

Hahn W.,West Virginia University | Ramotowski R.,United States Secret Service
Journal of Forensic Identification | Year: 2012

The purpose of this study was to evaluate the ability of a one-step fluorescent cyanoacrylate fuming process to develop latent fingerprints in comparison with the conventional two-step processes that are currently utilized worldwide. Such two-step methods involve the use of dye stains that contain organic solvents, which have a potential to damage the developed cyanoacrylate polymer as well as an item's substrate. The method described here involves the use of a prototype modified Foster and Freeman MVC 1000 cyanoacrylate fuming cabinet and a special powder that co-fumes along with the cyanoacrylate monomer. Latent prints aged up to three weeks were placed on a number of different substrates (e.g., sandwich bags, trash bags, bubble wrap, sheet protectors, and textured plastic substrates). Preliminary results indicate that this one-step process was effective at producing quality fluorescent prints on a number of the nonporous substrates. Although there were some substrates that did not work well with this new process, for the most part, the overall quality of the development was comparable to that achieved using the current two-step fuming and dye stain procedure.

Neumann C.,Pennsylvania State University | Ramotowski R.,United States Secret Service | Genessay T.,University of Lausanne
Journal of Chromatography A | Year: 2011

Forensic examinations of ink have been performed since the beginning of the 20th century. Since the 1960s, the International Ink Library, maintained by the United States Secret Service, has supported those analyses. Until 2009, the search and identification of inks were essentially performed manually. This paper describes the results of a project designed to improve ink samples' analytical and search processes. The project focused on the development of improved standardization procedures to ensure the best possible reproducibility between analyses run on different HPTLC plates. The successful implementation of this new calibration method enabled the development of mathematical algorithms and of a software package to complement the existing ink library. © 2010 Elsevier B.V.

Girod A.,University of Lausanne | Ramotowski R.,United States Secret Service | Weyermann C.,University of Lausanne
Forensic Science International | Year: 2012

This article describes the composition of fingermark residue as being a complex system with numerous compounds coming from different sources and evolving over time from the initial composition (corresponding to the composition right after deposition) to the aged composition (corresponding to the evolution of the initial composition over time). This complex system will additionally vary due to effects of numerous influence factors grouped in five different classes: the donor characteristics, the deposition conditions, the substrate nature, the environmental conditions and the applied enhancement techniques. The initial and aged compositions as well as the influence factors are thus considered in this article to provide a qualitative and quantitative review of all compounds identified in fingermark residue up to now. The analytical techniques used to obtain these data are also enumerated. This review highlights the fact that despite the numerous analytical processes that have already been proposed and tested to elucidate fingermark composition, advanced knowledge is still missing. Thus, there is a real need to conduct future research on the composition of fingermark residue, focusing particularly on quantitative measurements, aging kinetics and effects of influence factors. The results of future research are particularly important for advances in fingermark enhancement and dating technique developments. © 2012 Elsevier Ireland Ltd.

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