Detection and mapping of illicit drugs and their metabolites in fingermarks by MALDI MS and compatibility with forensic techniques

Despite the proven capabilities of Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDI MS) in laboratory settings, research is still needed to integrate this technique into current forensic fingerprinting practice. Optimised protocols enabling the compatible application of MALDI to developed fingermarks will allow additional intelligence to be gathered around a suspect’s lifestyle and activities prior to the deposition of their fingermarks while committing a crime. The detection and mapping of illicit drugs and metabolites in latent fingermarks would provide intelligence that is beneficial for both police investigations and court cases. This study investigated MALDI MS detection and mapping capabilities for a large range of drugs of abuse and their metabolites in fingermarks; the detection and mapping of a mixture of these drugs in marks, with and without prior development with cyanoacrylate fuming or Vacuum Metal Deposition, was also examined. Our findings indicate the versatility of MALDI technology and its ability to retrieve chemical intelligence either by detecting the compounds investigated or by using their ion signals to reconstruct 2D maps of fingermark ridge details

Mechanistic insight into the fluorescence activity of forensic fingerprinting reagents.

Fingerprint detection is still the primary investigative technique for deciphering criminal inquiries and identifying individuals. The main forensic fingerprinting reagents (FFRs) currently in use can require multiple treatment steps to produce fingerprints of sufficient quality. Therefore, the development of new, more effective FFRs that require minimal chemical treatment is of great interest in forensic chemistry. In this work, prudently crafted density functional theory and time-dependent density functional theory calculations are utilized to derive mechanistic insight into the optical activity of the non-fluorescent product of ninhydrin, diketohydrindylidenediketohydrindamine (DYDA), and fluorescent product of DFO (1,8-diazafluoren-9-one). We investigate various protonation sites to gain an understanding of isomeric preference in the solid-state material. A relaxed scan of a single torsion angle rotation in the S minimized geometry of the O-protonated DYDA isomer suggests a conical intersection upon ∼10° rotation. We show that the absence of a rigid hydrogen-bonded network in the crystal structure of DYDA supports the hypothesis of torsion rotation, which leads de-excitation to occur readily. Conversely, for the fluorescent DFO product, our calculations support an avoided crossing suggestive of a non-radiative mechanism when the torsion angle is rotated by about ∼100°. This mechanistic insight concurs with experimental observations of fluorescence activity in DFO and may aid the photophysical understanding of poorly visualized fingerprints due to weak fluorescence. We show that identifying suggestive avoided crossings via the method described here can be used to initialize thoughts toward the computational design of FFRs

Visualising the past – an evaluation of processes and sequences for fingermark recovery from old documents

This study aimed to collect data on the effectiveness of most of the fingermark visualisation reagents currently used on porous surfaces on fingermarks aged for up to 90 years, significantly extending the timescales for which such information exists. A limited subset of the variables associated with processing of old fingermarks was explored, with a focus on the use of 1,8 diazafluoren-9-one (DFO), 1,2-indandione, ninhydrin, and physical developer. These techniques were used in sequence on batches of cheques between 11 and 32 years old, and on documents dating from the 1920s and 1940s. The potential for applying a physical developer enhancement process (blue toning) as the final step in the sequence was also explored. The benefits of using processing sequences on porous items were clearly demonstrated, with all processes in the sequence adding value in terms of additional marks found on the cheques up to 32 years old. In addition, physical developer was found to be capable of developing fingermarks up to 90 years old, whereas the amino acid reagents appear less effective on documents of 70 years and older. An experimental physical developer formulation with reduced environmental impact was found to be as effective as the existing process in these experiments. Blue toning was found to visualise an additional 10-25% of marks, and its wider use after silver-based deposition processes is recommended based on the evidence from this study.Peer reviewedFinal Accepted Versio

Variability and subjectivity in the grading process for evaluating the performance of latent fingermark detection techniques

When assessing latent fingermark development methods, forensic researchers commonly evaluate treated samples using a grading scale. However, the subjective nature of these evaluation methods leaves the results of such investigations open to criticism for potential grader bias. Assessment of fingermark development quality is ultimately dependent on an individual's background and experience. A pilot study was conducted as a preliminary stage of a large-scale international collaboration. A set of 80 fingermark samples was developed with 1,2-indanedione-zinc chloride. Grades for photographic images of the developed fingermarks were assigned independently by 11 fingermark researchers. Sixty-seven percent of the scores given to each individual sample were the same as the median grade, and 99% of the scores were within 1 grade. The researchers were also assessed on their consistency by including 20 duplicate images to be graded. Seventy-eight percent of the grades given were identical to their original scores. These results indicate that a small group of independent fingermark graders is sufficient to produce reliable and consistent data in projects requiring the assessment of fingermark quality

The visualisation of fingermarks on Pangolin scales using gelatine lifters

Recent media reports document the plight of the Pangolin and its current position as “the most trafficked mammal in the world”. They are described by some as scaly anteaters as all species are covered in hard keratinous tissue in the form of overlapping scales acting as a “flexible dermal armour”. It is estimated that between 2011 and 2013, 117,000–234,000 pangolins were slaughtered, but the seizures may only represent as little as 10% of the true volume of pangolins being illegally traded. In this paper, methods to visualise fingermarks on Pangolin scales using gelatine lifters is presented. The gelatine lifters provide an easy to use, inexpensive but effective method to help wildlife crime rangers across Africa and Asia to disrupt the trafficking. The gelatine lifting process visualised marks producing clear ridge detail on 52% of the Pangolin scales examined, with a further 30% showing the impression of a finger with limited ridge detail. The paper builds on an initial sociotechnical approach to establishing requirement, then it focuses on the methods and outcomes relating to lifting fingermarks off Pangolin scales using gelatine lifters, providing an evaluation of its use in practice

The visualisation on Pangolin scales using gelatine lifters

Recent media reports document the plight of the Pangolin and its current position as “the most trafficked mammal in the world”. They are described by some as scaly anteaters as all species are covered in hard keratinous tissue in the form of overlapping scales acting as a “flexible dermal armour”. It is estimated that between 2011 and 2013, 117,000 to 234,000 pangolins were slaughtered, but the seizures may only represent as little as 10% of the true volume of pangolins being illegally traded. In this paper, methods to visualise fingermarks on Pangolin scales using gelatine lifters is presented. The gelatine lifters provide an easy to use, inexpensive but effective method to help wildlife crime rangers across Africa and Asia to disrupt the trafficking. The gelatine lifting process visualised marks producing clear ridge detail on 52% of the Pangolin scales examined, with a further 30% showing the impression of a finger with limited ridge detail. The paper builds on an initial sociotechnical approach to establishing requirement, then it focuses on the methods and outcomes lifting fingermarks off Pangolin scales using gelatine lifters, providing an evaluation of the viability of using the lifters in practice

Non-invasive detection and chemical mapping of trace metal residues on the skin

Residual traces of the metals copper and lead on an individual's skin may be elucidated by reaction of rubeanic acid with a gelatine lift taken from the target area in question, yielding intensely coloured reaction products. This non-invasive technique has been shown to offer promise in chemically mapping the distribution of the minute metal residues across an individual's hand deposited through touching metal items, a technique with potential forensic significance

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 December 2010-31 January 2011

This article documents the addition of 238 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Alytes dickhilleni, Arapaima gigas, Austropotamobius italicus, Blumeria graminis f. sp. tritici, Cobitis lutheri, Dendroctonus ponderosae, Glossina morsitans morsitans, Haplophilus subterraneus, Kirengeshoma palmata, Lysimachia japonica, Macrolophus pygmaeus, Microtus cabrerae, Mytilus galloprovincialis, Pallisentis (Neosentis) celatus, Pulmonaria officinalis, Salminus franciscanus, Thais chocolata and Zootoca vivipara. These loci were cross-tested on the following species: Acanthina monodon, Alytes cisternasii, Alytes maurus, Alytes muletensis, Alytes obstetricans almogavarii, Alytes obstetricans boscai, Alytes obstetricans obstetricans, Alytes obstetricans pertinax, Cambarellus montezumae, Cambarellus zempoalensis, Chorus giganteus, Cobitis tetralineata, Glossina fuscipes fuscipes, Glossina pallidipes, Lysimachia japonica var. japonica, Lysimachia japonica var. minutissima, Orconectes virilis, Pacifastacus leniusculus, Procambarus clarkii, Salminus brasiliensis and Salminus hilarii

Home Office Fingerprint Source Book

The Fingerprint Source Book is primarily intended to provide the background and validation for the techniques currently (up to 2016) recommended by the Home Office Centre for Applied Science and Technology (CAST), and to publish, in some cases for the first time, data collected over 45 years of research. It will therefore often present information in an ‘CASTcentric’ way, emphasising research that was carried out at Sandridge or Horseferry House, possibly sometimes at the expense of research carried out elsewhere. It is not the intention of the authors to ignore the significant contributions made by other research groups and apologies are made in advance if this sometimes appears to be the case. The document is also aimed at providing the UK Forensic Science Regulator and the United Kingdom Accreditation Service (UKAS), which has carried out ISO 17025 accreditation in the UK, with the background evidence behind the advice given in the Fingermark Visualisation Manual

The Reed-Stanton press rig for the generation of reproducible fingermarks : towards a standardised methodology for fingermark research

In the search for better or new methods/techniques to visualise fingermarks or to analyse them exploiting their chemical content, fingermarks inter-variability may hinder the assessment of the method effectiveness. Variability is due to changes in the chemical composition of the fingermarks between different donors and within the same donor, as well as to differential contact time, pressure and angle. When validating a method or comparing it with existing ones, it is not always possible to account for this type of variability. One way to compensate for these issues is to employ, in the early stages of the method development, a device generating reproducible fingermarks. Here the authors present their take on such device, as well as quantitatively describing its performance and benefits against the manual production of marks. Finally a short application is illustrated for the use of this device, at the method developmental stages, in an emerging area of fingerprinting research concerning the retrieval of chemical intelligence from fingermarks