Migration of latent fingermarks on non-porous surfaces:observation technique and nanoscale variations

Latent fingermark morphology was examined over a period of approximately two months. Variation in topography was observed with atomic force microscopy and the expansion of the fingermark occurred in the form of the development of an intermediate area surrounding the main fingermark ridge. On an example area of a fingermark on silicon, the intermediate region exists as a uniform 4nm thick deposit; on day 1 after deposition this region extends approximately 2µm from the edge of the main ridge deposit and expands to a maximum of ~ 4µm by day 23. Simultaneously the region breaks up, the integrity is compromised by day 16, and by day 61 the area resembles a series of interconnected islands, with coverage of approximately 60%. Observation of a similar immediate area and growth with time on surfaces such as Formica was possible by monitoring the mechanical characteristics of the fingermark and surfaces though phase contrast in tapping mode AFM. The presence of this area may affect fingermark development, for example affecting the gold distribution in vacuum metal deposition. Further study of time dependence and variation with donor may enable assessment of this area to be used to evaluate the age of fingermarks

Water-soaked porous evidence:a comparison of processing methods

This study compared the U.K. Home Office formulation for physical developer (PD) against Oil Red O (ORO) and a modified formulation of physical developer (MPD) that uses Tween 20 instead of Synperonic-N for enhancing fingermarks. Three different donors deposited fingermarks on porous surfaces (white paper, leaflets, and cardboard), with aging periods varying from 7 to 28 days. None of the techniques that were tested provided enhancement of latent fingermarks on leaflets, whereas poor-quality enhancement was observed on cardboard. In contrast, all techniques were more successful on white paper surfaces. The results obtained on white paper suggested that PD and MPD performed similarly, with PD detecting 82.3% of the deposited fingermarks and MPD detecting 86.5% of the deposited fingermarks. PD yielded a higher percentage (38.5%) of fingermarks with fine ridge detail (i.e., those with grade 2 or above) than MPD (35.4%). ORO, however, yielded poor results, enhancing only 4.5% of latent fingermarks, but showed no ridge detail in any of the enhancements (i.e., only showed grade 1 enhancements.

A review of one-step fluorescent cyanoacrylate techniques

A review of recent research in the use of one-step fluorescent cyanoacrylate techniques is presented. Advantages and disadvantages of such techniques in comparison to two-step processes are discussed. Further studies and new experimental data are presented to aid this review: three one-step cyanoacrylate products (Lumicyano, PolyCyano UV and PECA Multiband) containing a fluorescent dye were tested to evaluate their effectiveness in developing latent fingermarks on polyethylene bags by means of a pseudo operational trial. The results were compared to the traditional two-step process of cyanoacrylate fuming followed by staining with ethanol-based basic yellow 40 (BY40). The study was conducted using sequential treatments of an initial fuming cycle, a second cycle and finally BY40 staining. LumicyanoTM and PolyCyano UV performed similarly before BY40 staining, with both providing good contrast and visibility under fluorescence. PECA Multiband, however, did not develop as many fingermarks and proved to be problematic for the fuming cabinet. Subsequent BY40 staining of fingermarks developed by all three one-step processes enabled the visualisation of new fingermarks

A competitive enzyme immunoassay for the quantitative detection of cocaine from banknotes and latent fingermarks

A sensitive and versatile competitive enzyme immunoassay (cEIA) has been developed for the quantitative detection of cocaine in complex forensic samples. Polyclonal anti-cocaine antibody was purified from serum and deposited onto microtiter plates. The concentration of the cocaine antibody adsorbed onto the plates, and the dilution of the cocaine-HRP hapten were both studied to achieve an optimised immunoassay. The method was successfully used to quantify cocaine in extracts taken from both paper currency and latent fingermarks. The limit of detection (LOD) of 0.162 ng mL-1 achieved with the assay compares favourably to that of conventional chromatography-mass spectroscopy techniques, with an appropriate sensitivity for the quantification of cocaine at the low concentrations present in some forensic samples. The cEIA was directly compared to LC-MS for the analysis of ten UK banknote samples. The results obtained from both techniques were statistically similar, suggesting that the immunoassay was unaffected by cross-reactivity with potentially interfering compounds. The cEIA was used also for the detection of cocaine in extracts from latent fingermarks. The results obtained were compared to the cocaine concentrations detected in oral fluid sampled from the same individual. Using the cEIA, we have shown, for the first time, that endogeneously excreted cocaine can be detected and quantified from a single latent fingermark. Additionally, it has been shown that the presence of cocaine, at similar concentrations, in more than one latent fingermark from the same individual can be linked with those concentrations found in oral fluid. These results show that detection of drugs in latent fingermarks could directly indicate whether an individual has consumed the drug. The specificity and feasibility of measuring low concentrations of cocaine in complex forensic samples demonstrates the effectiveness and robustness of the assay. The immunoassay presents a simple and cost-effective alternative to the current mass spectrometry based techniques for the quantitation of cocaine at forensically significant concentrations

The effect of cyanoacrylate fuming on subsequent protein stain enhancement of fingermarks in blood

This study investigates the effect of cyanoacrylate (CA) fuming, at atmospheric and vacuum conditions, on subsequent protein stain (acid violet 17) enhancement of fingermarks in blood. Fingermark depletions in blood were deposited on three nonporous surfaces (e.g., plastic bag) and aged for a set period of time (up to 28 days) before enhancement with the water-ethanol-acetic acid and methanol formulations of acid violet 17 (AV17). All trials were carried out in duplicate. One depletion was pre-treated with CA fuming followed by the enhancement technique and the other depletion was treated with only the enhancement technique (control).As expected, atmospheric CA fuming hindered the subsequent enhancement of blood with the AV17 water-ethanol-acetic acid formulation but not the methanol formulation. The same observations were also recorded under vacuum CA fuming conditions. Preliminary work with vacuum metal deposition did not hinder subsequent AV17 protein stain enhancement with either formulation

An investigation into the detection of latent marks on the feathers and eggs of birds of prey

There are numerous enhancement techniques (physical and chemical) which have been developed for the successful visualisation of latent fingermarks. Nonetheless, problems arise when latent fingermarks require enhancement on difficult surfaces such as human skin, food stuffs, fabric and animals. The ability to develop latent fingermarks on the surface of bird of prey feathers and that of their eggs was investigated. Red and green magnetic fluorescent powders proved to be most suitable on the surface of bird of prey feathers whereas black magnetic powder was the most suitable technique on the eggs. These powders produced the highest quality of visible ridge-detailed developments over a controlled period of time

Environmental effects on magnetic fluorescent powder development of fingermarks on bird of prey feathers

A comparison study of the effects of environmental conditions on the development of latent fingermarks on raptor feathers using green magnetic fluorescent powder was undertaken using both sebaceous loaded and natural fingermark deposits. Sparrowhawk feathers were stored in indoor conditions for 60 days (Study 1), and buzzard feathers were left exposed to two different environmental conditions (hidden and visible) for 21 days (Study 2), with developments made at regular ageing periods. In Study 1, latent fingermarks were successfully developed (Grade 1–4) on the indoor feathers up to 60 days after deposition – 98.6% of the loaded deposits and 85.3% for natural deposits. Under outdoor conditions in Study 2, both loaded and natural deposits were affected by environmental exposure. Latent fingermarks were successfully developed up to 14 days after deposition on the outdoor feathers, with some occasional recovery after 21 days. The visible feathers recorded 34.7% (loaded) and 16.4% (natural) successful developments (Grade 1–4), whereas the hidden feathers recorded 46.7% (loaded) and 22.2% (natural) successful developments, suggesting that protection from the environment helps to preserve latent fingermarks on the surface of a feather. Environmental exposure accelerated the deterioration of ridge detail and the number of successful developments

Metal-containing nanoparticles and nano-structured particles in fingermark detection

This article reviews the application of metal-containing nanoparticles and nano-structured particles to fingermark detection. This area of research is attracting significant interest as advances in nanoscience are being incorporated into the field of forensic fingermark detection. Although more research is needed before some of the techniques presented can be implemented in routine casework, nanotechnology is likely to play a major role in the future to deliver more selective and more sensitive ways to detect and enhance fingermarks. © 2008 Elsevier Ireland Ltd. All rights reserved

Visualisation of fingermarks and grab impressions on dark fabrics using silver vacuum metal deposition

Vacuum metal deposition (VMD) involves the thermal evaporation of metal (silver) in a vacuum, resulting in a uniform layer being deposited on the specimen being treated. This paper examines the use of silver on dark fabrics, thus offering a simpler operation and more obvious colouration to that of the traditional use of gold and zinc metals which must be evaporated separately. The aim of this study was to investigate the effect of fabric type, donor, mark age and method of fingermark deposition on the quality of marks visualised using silver VMD. This was achieved by collecting fingermark deposits from fifteen donors, of both sexes and various ages, by a grab or a press method. Four different fabrics: satin, polyester, polycotton and cotton were studied over a 10 day timeline of 1, 2, 3, 4, 5, 6, 7, 14, 21 and 28 + days. It was found that satin and polyester gave the most positive results, with polyester often producing excellent ridge detail. Cotton and polycotton were less successful with no ridge detail being observed. The donors also had an observable effect on the results obtained probably due to variations in secretions produced or pressures applied during specimen collection. The age of the mark or the method of mark deposition had little influence on the results obtained. Silver VMD is a viable process for visualising marks on certain dark fabrics and has the advantage over gold/zinc VMD in that the marks visualised are light in colour which contrasts well against the dark background

Interpol review of fingermarks and other body impressions 2016–2019

This review paper covers the forensic-relevant literature in fingerprint and bodily impression sciences from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/ 14458/file/Interpol%20 Review%20 Papers%202019. pdf