Enhancement Of Fingermarks Research Articles

A stain with all the fixing’s – Enhancement of fingermarks in blood using a combined fixative and aqueous protein stain

The use of protein stains to enhance fingermark ridge detail in blood is a common technique used by forensic practitioners around the world. Amido Black is one of the most favoured protein stains due to its strong staining ability. The most common formulation of Amido Black is methanol based, with an ability to simultaneously fix and stain the blood impression, however methanol is toxic and can disrupt some surfaces, potentially compromising fingermark detail. If the surface is suspected of being a material that is impacted by methanol, there is an alternative aqueous formulation, which requires a fixative step to set the blood prior to staining so as not to wash away potential ridge detail. The multi-step process of aqueous protein stains is tedious and numerous studies have been conducted to improve the formula to achieve a combined fixing/staining solution that performs like the methanolic reagent. A combined fixative and stain formulation of aqueous based Amido Black was compared to a multi-step formulation with a separate sulfosalicylic acid fixative. Of the 243 split fingermark impressions analysed the majority (63.5 %) showed no preference to either treatment, with a marginally greater proportion of the remaining marks slightly favouring the combined fixative and stain formulation. Given that the new combined formulation performed broadly similarly to the existing multi step formulation, the potential time savings of this simpler approach may be beneficial to implement into operational use.

The influence of storage conditions on fingermarks developed with 1,2-indanedione-ZnCl

The most important class of reagents for the enhancement of fingermarks on porous surfaces are those that react with the amino acid constituents of fingermarks. Ninhydrin, DFO (1,8-diazafluoren-9-one), and 1,2-indanedione are the three most common techniques widely known in forensic laboratories for the visualization of latent fingermarks on porous surfaces. In 2012 the Netherlands Forensic Institute replaced DFO by 1,2-indanedione-ZnCl after an internal validation, just like an increasing numbers of laboratories. In 2003, Gardner et al. published an article showing that fingermarks treated with 1,2-indanedione (without ZnCl), that were stored in daylight only decreased by 20% in fluorescence in 28 days. However, during casework we observed that the fluorescence of fingermarks treated with 1,2-indanedione with ZnCl decreased more rapidly. In this study, the effect of various storage conditions and aging times on the fluorescence of marks after treatment with 1,2-indanedione-ZnCl were assessed. Latent printed fingermarks from the digital matrix printer (DMP) and natural fingermarks from a known donor were used. The results showed that storing fingermarks in daylight (wrapped and un-wrapped) drastically decrease (over 60% loss) in fluorescence in approximately three weeks. Storage of the marks in a dark environment (at room temperature, in the refrigerator or even in the freezer) resulted in a decrease in fluorescence of less than 40%. Our recommendation is to always store treated fingermarks with 1,2-indanedione-ZnCl in a dark environment and, if possible, photographing them directly (within 1–2 days after treatment) to minimize the decrease of fluorescence.

Quantitative evaluation of latent fingermarks with novel enhancement and illumination

A variety of suspended silica and metal nanoparticles have been used over the last 20 years to enhance latent fingermarks. This study quantitatively evaluates enhancement of natural and sebum-enriched fingermarks from three adult subjects acquired with a consistent applied force on glass with a fingermark press using suspended commercially available polystyrene (PS) particles. Images of the enhanced fingermarks acquired with total internal reflection (TIR), or standard overhead white light (WL), illumination are compared with fingermarks enhanced with conventional methods including cyanoacrylate fuming. The different enhancement and illumination methods are quantified based on the brightness and contrast of the fingermark images, as well as the number of minutiae that can be identified and matched to those on an inked manually acquired “template” fingermark using automatic fingerprint identification system (AFIS) software. Enhanced fingermarks acquired with the press are shown to be more consistent than manually acquired fingermarks based on these metrics. The results demonstrate that TIR illumination from a large-area illuminator built in house gives enhanced fingermark images with more matched minutiae and contrast superior to that for WL illumination for all types of enhancement. “Wet-powdering” with PS particles gives fingermark images that are for the most part comparable in terms of the number of matched minutiae to fingermarks enhanced with more conventional methods, suggesting that this novel enhancement method has a performance comparable to conventional enhancement methods. Interestingly, the age of the fingermark appears to have almost no effect on this new type of enhancement; sebum-enriched fingermarks ranging in age from 12 h to 435 days appear to have statistically identical numbers of matched minutiae.

Novel O‐propyl, S‐propyl, and N‐propyl substituted 1,4‐naphthoquinones and 1,4‐anthraquinones as potential fingermark development reagents for porous surfaces

Lawsone is a 2-substituted-1,4-naphthoquinone derivative, which has been proposed as an alternative to the reagents currently used for fingermark detection on porous surfaces. 2-substituted-anthraquinones, which contain an additional conjugated benzene ring, have a similar chemical structure to that of lawsone. In this study, a new series of 2-substituted-1,4-naphthoquinones and 2-substituted-1,4-anthraquinones were synthesized and completely characterized by1 H NMR,13 C NMR, IR, and HPLC-TOF/MS analyses. All newly synthesized 2-substituted-1,4-quinones were investigated for their ability to develop latent fingermarks on porous surfaces, and this ability was compared with that of lawsone. Each fingermark developed was graded using an established method; thus, quantitative data were attributed to each fingermark. It has been demonstrated that the 1,4-quinones react with amino acids present in latent fingermarks on selected paper surfaces to produce faint yellow-orange impressions, which exhibit strong photoluminescence when illuminated with a forensic light source at 440nm and observed through a red filter. None of the compounds caused background darkening. The results obtained were generally similar to those of lawsone, however, 8-dibromo-2-(propylamino)naphthalene-1,4-dione and 5,8-dibromo-2-(propylthio)naphthalene-1,4-dione yielded better results for copier paper and colored (blue) copier paper used in this analysis. To the best of our knowledge, this is the first study to examine the role of 1,4-anthraquinone derivatives as potential fingermark development reagents. The results indicate that 1,4-quinones have a potential to be used as reagents for enhancement of latent fingermarks.

Latent fingermarks on copperplate paper: facile visualization via electrochromism of 1,1′-bis(3-sulfonatopropyl) viologen

Visualization of latent fingermarks has ever been realized through electrochromism (EC) on stainless steel used as an electrode of electrochromic device (ECD). However, enhancement of fingermarks on paper using EC remains unresolved. Considering the hydrophobicity differences between the protruding and the concave parts of sebum-containing fingermarks, we attempt to devise ECDs capable of visualizing latent fingermarks on copperplate paper. It is demonstrated that the sulfonated viologen, 1,1′-bis(3-sulfonatopropyl) viologen can be used as an excellent chromophore for latent fingermarks enhancement on copperplate paper using EC, with either 1,1′-ferrocenedimethanol, or vitamin C or potassium ferrocyanide/potassium ferricyanide as the electron mediator. The as-fabricated ECDs can display the characteristic second level details of latent fingermarks left on copperplate paper under a voltage of -1.2 V. This work opens a new avenue for visualizing latent fingermarks on copperplate paper, which is a frequently-used potential physical evidence in office and daily life that may be useful for forensics.

Evaluation of the performance of IND/Zn and DFO on various porous substrates in Singapore context

Enhancement of latent fingermarks found at crime scenes can be crucial to criminal investigations. The performance of ninhydrin analogues 1,2-indanedione (IND/Zn) and 1,8-diazafluoren-9-one (DFO) used in laboratories for the enhancement of latent fingermarks on porous substrates were compared for operational use. The visualisation of enhanced latent fingermarks on seven substrates commonly encountered in local crimes - plain A4 paper, glossy magazine, paper magazine, brown envelopes, white envelopes, cardboard, and joss paper were assessed using fingermarks deposits from seven donors. Fingermarks were aged under both indoor and outdoor conditions as well as over different periods of time. Our results show that IND/Zn consistently produced fingermarks of superior quality and contrast to DFO across the different donors, substrates and time periods. IND/Zn also appears to be more sensitive compared to DFO.

Determination of the most effective enhancement process for latent fingermarks on Clydesdale Bank and Royal Bank of Scotland £5 and £10 polymer banknotes

Fingermarks are commonly found at crime scenes and can be used to link an individual to an object and/or place. One common evidence type regularly encountered in the course of a criminal investigation is banknotes, and the recovery of fingermarks from these notes can give an indication of who has handled them. This study was carried out in order to determine the most effective sequential processing techniques for recovering latent fingermarks on the new £5 and £10 Clydesdale Bank and Royal Bank of Scotland polymer banknotes. No previous studies have been published on the recovery of latent fingermarks from these types of polymer notes; therefore, this work provides valuable insight into the challenges associated with these notes. Initial experimentation was done in order to determine the best light source to be used in combination with each sequential process tested. From this, infrared (730–800nm) and ultraviolet (350–380nm) light were chosen for use in the main study. Black iron oxide powder suspension and black magnetic powder were two of the enhancement treatments tested, both of which are recommended ‘Category A’ processes in the Fingermark Visualisation Manual produced by the Home Office. Superglue fuming – using PolyCyano UV—which is a Category C process was also used, as well as the recently developed infrared fluorescent powder, fpNATURAL®2. Three fingermark donors were selected for this study—one good, one medium and one poor—and each donor deposited a 10-mark depletion series onto both sides of each type of note. Superglue fuming (using PolyCyano UV) followed by black magnetic powder was found to be the most effective sequential process for enhancement of fingermarks on all note types tested. Infrared (730–800nm) light with an 815nm filter was the most effective light source for enhancing ridge detail for this enhancement sequence. This process is now being implemented for use with these note types in Scotland.

The effect of paint type on the development of latent fingermarks on walls

Despite recent advances in DNA technology, fingermark evidence remains a fundamental method of ascertaining an individual’s identity. Latent fingermarks are the commonest type of fingermark encountered at crime scenes. The Fingermark Visualisation Manual provides crime scene practitioner’s with sequential information regarding which enhancement processes are best suited for a range of deposition surfaces (Bandey et al., 2014) [1]. However, there are still many surfaces, such as painted walls where more knowledge is required regarding which development techniques provide optimum results. In this study, four paint types were tested (matt, silk, bathroom and eggshell). Fingermarks were deposited on painted simulated walls and aged for 1 day, 1 week and 1 month. Fingermarks were developed by three processes highlighted as the most frequently used by practitioners (magnetic granular powder, magneta flake powder and ninhydrin). The results showed that overall black magnetic granular powder outperformed both magneta flake powder and ninhydrin on all paint types. This contradicts current UK guidelines for enhancement of fingermarks on matt painted walls, as black magnetic granular powder is not a recommended process at present. SEM and SEM-EDX analysis showed distinct differences between matt paint and the three non-matt paints tested, which provides an explanation for the results obtained.

The optimisation of fingermark enhancement by VMD and Lumicyano™ on thermal paper

The enhancement of fingermarks on thermal paper can be challenging due to background staining caused by polar solvents used in fingermark enhancement techniques such as ninhydrin. This study explored a commercial one-step superglue fuming process, Lumicyano™, and Vacuum Metal Deposition (VMD) to develop fingermarks on this substrate and overcome this issue. Different sequential treatments involving Lumicyano™ and a combination of VMD methods were investigated with varying degrees of success with some sequences being highly sensitive. The VMD processes, however, were observed to generally be more effective at enhancing marks, whereas Lumicyano™ provided little or no benefit on this paper type. The results indicate that Lumicyano™ is only beneficial as a pre-treatment when the entire sequence of gold/zinc and silver/zinc is taken to completion. The gold/zinc and silver/zinc VMD processes were optimised on five different thermal papers, and the optimised techniques were then directly compared to determine which was more successful on each thermal paper type as a single treatment.

Evaluation of a Hot Print System for the development of latent fingermarks on thermal paper: A pseudo-operational trial

Enhancement of latent fingermarks on thermal paper poses a number of problems when using traditional methods used for porous substrates due to blackening of the thermal layer as a result of polar solvents present within the reagents and high temperatures oxidising the acid/dye complex. Thus, methods which prevent such reactions are favoured for the development of latent prints on said substrates. A comparative pseudo-operational trial using UV, Hot Print System (HPS), ninhydrin and ThermaNIN was performed on 1000 thermal paper substrates gathered from various sources. The results indicated that the most effective method was an acetone pre-wash followed by ninhydrin. The sequence of HPS-ninhydrin was similarly effective when compared to ninhydrin as a sole technique. ThermaNIN produced fewer marks than ninhydrin but was superior to HPS. Whilst the HPS developed some fingermarks, there was only a very small number of marks uniquely developed by it.

Enhancement of fingermarks and visualizing DNA

A novel method for detection and visualization of latent DNA using Diamond™ Nucleic Acid Dye (DD) staining has been developed. Applying DD to an object has the real potential to visualize DNA on a substrate from which a DNA profile can be generated, but it is important to determine whether this staining will adversely affect other forensic investigational techniques and vice versa.The aim of this study was to examine the interactions between staining a fingermark to detect DNA and then generate a DNA profile in combination with several standard latent fingermark enhancement methods. Six common fingerprint enhancements processes were chosen; (1) black powder, (2) black magnetic powder, (3) red magnetic powder, (4) white powder, (5) aluminum powder and (6) cyanoacrylate fuming. For all six methods, mark enhancement was carried out before DD staining and vice versa. DD is effective in detection of DNA in the presence of both aluminum and white finger mark powders and DD does not compromise the subsequent detection of ridge patterns if DD is applied first. Whilst magnetic powders could be used to successfully enhance latent fingermarks even after DD had been applied to them, latent DNA could not be observed in the marks irrespective of whether magnetic powder was applied before or after DD treatment. Magnetic powders did not adversely affect the profiling of DNA present in the marks. The application of DD to fingermarks did not adversely affect the enhancement of fingermarks using cyanoacrylate fuming. Whilst fluorescent particles resembling cells stained with DD were observed in marks either post-treated or pre-treated with cyanoacrylate vapor, DNA amplification and profiling was not successful.While it may be important in particular investigations to collect DNA profiles from latent fingermarks with continuous ridges and clear minutiae, the main utility of the technique described here would be in relation to investigations where enhancement has resulted in only partial or smudged marks. The results presented here indicate that if it is desirable to visualize latent DNA on an object but it is also planned to treat the object with cyanoacrylate vapor or magnetic powders then it is important to apply DD first, record the location of DNA and then apply the mark enhancement technique. For aluminum and white powder mark treatments such precautions are not important.

Fluorescent metal organic frameworks for the visual enhancement of latent fingermarks

Lanthanide-based (Eu and Tb) metal organic frameworks (MOFs) synthesized in this work are highly fluorescent crystalline structures that form through a self-assembly process in an aqueous environment. Various bio-organic molecules, including proteins and amino acids, can act as inducing agents for this process. The fact that these components are present in fingermark secretions, in combination with the excellent luminescent properties of the MOFs, create a visualisation method for (latent) fingermarks. The aqueous MOF precursor solutions are not ideal for the visualisation of latent fingermarks on non-porous surfaces, such as aluminium foil and glass. However, they offer a simple, non-toxic, long-lasting and effective approach for the visibility enhancement of fingermarks treated with cyanoacrylate fuming on aluminium foil and glass and latent fingermarks on the adhesive side of a transparent tape. The luminescent properties of MOF-treated fingermarks persevered for at least 12 months, providing great alternative for commonly used organic dyes such as Basic Yellow 40 and Gentian Violet. In this communication we evaluate the applicability of the proposed method for the forensic fingermark workflow.

Silver-assisted development and imaging of fingermarks on non-porous and porous surfaces

In order to deal with the range of surfaces encountered in crime scenes and items associated with crimes, forensic fingermark examiners must have access to a range of latent mark enhancement techniques, each compatible with a particular type of surface. Consequently, the development of techniques with universal or even wide-ranging surface compatibility would be valuable to law enforcement.Herein, we describe a one-step silver sputtering method for the enhancement of latent fingermarks on plastic, glass, paper and metal substrates. This method allows for the ridge pattern to be captured for human identification purposes and, more importantly, for the downstream mass spectrometric imaging of the fingermark in order to display the spatial distribution of common endogenous and exogenous substances such as illicit drugs

A simple combustion method for the synthesis of multi-functional ZrO2/CuO nanocomposites: Excellent performance as Sunlight photocatalysts and enhanced latent fingerprint detection

A facile solution combustion synthesis has been adopted to synthesize ZrO2/CuO nanocomposite oxides (NCO’s) by utilizing Oxalyl dihydrazide (ODH) as fuel. The X-ray diffraction patterns and TEM analysis reveals the presence of cubic ZrO2 and CuO in ZrO2/CuO NCO’s. The NCO’s synthesized by simple, fast, highly sensitive and low-cost method is found to be an alternate to traditional luminescent powders for the detection and enhancement of finger marks in a broad range of surfaces. The photoluminescence analysis indicates that the present NCO is an effective blue component in display applications. The synthesized ZrO2/CuO (2:1) composite exhibited excellent photocatalytic activity towards the degradation of various dyes under Sunlight. In particular, Indigo carmine dye was chosen to explore the photocatalytic performance of prepared NCO’s under Sunlight illumination. It was found that ZrO2:CuO (2:1) NCO showed enhanced photocatalytic activity of 97% which was found to be 3.3 times 2.4 times and 1.5 times higher than that of pure ZrO2, CuO and commercial P25. This can be mainly attributed to the balance between the parameters, band gap, nature of morphology, crystallite size, defects and surface area which causes a slow electron-hole pair recombination rate with fast electron transfer ability. It opens new window to use this simple method to synthesize multifunctional character ZrO2-based composite materials in the area of photocatalysis particularly waste water treatment, display applications as well as a labeling agent to enhance latent fingerprints.

Superstructures of doped yttrium aluminates for luminescent and advanced forensic investigations

Nanocrystalline Tb3+ (1–11mol %) doped YAlO3 phosphors were prepared by biocompatible combustion route using Aloe Vera gel as a fuel. The average crystallite sizes were estimated using XRD and TEM found to be ∼27 nm. Scanning electron micrographs showed microlayered superstructures of various shapes of uniform particles. Upon 341 nm excitation, the photoemission profile of YAlO3: Tb3+ exhibit a narrow green emission peak at 545 nm due to 5D4→7F5 transition. Optical parameters such as Judd–Ofelt parameters, radiative transition probabilities, radiative lifetimes, branching ratio, stimulated emission cross-section and optical gain were estimated by Judd–Ofelt theory. CIE coordinate for the optimized phosphor was (x = 0.308, y = 0.435) which is very close to NTSC standard value for green emission. Further, the correlated color temperature was estimated and found to be ∼6178 K. A simple, fast, highly sensitive and ecofriendly method for the detection and enhancement of fingermarks in various forensic relevant materials was presented.

Development of fingermark on the surface of fired cartridge casing using amino acid sensitive reagents: Change of viewpoint

Four amino acid sensitive fingermark enhancement reagents (ninhydrin, 5-methylthioninhydrin (5-MTN), 1,8-diazafloren-9-one (DFO), 1,2-indandione (1,2-IND) were used for the development of fingermark on the surface of brass. The reagents were used for the detection of a trace amount of metallic ion on the surface of cartridge casings to develop latent fingermarks. Ninhydrin-l-alanine (NIN-ALA), 5-MTN-l-alanine (MTN-ALA), DFO-l-alanine (DFO-ALA), 1,2-IND-l-alanine (IND-ALA) complexes were prepared and applied to the fired cartridge casings, for the further enhancement of fingermarks developed by corrosion on the surface of brass. Of the four complexes, NIN-ALA and MTN-ALA complexes induced color changes to enhance fingermarks on fired cartridge casings, but photoluminescence was not observed. About 31% of cartridge casings treated with MTN-ALA showed enhanced fingermarks. DFO-ALA and IND-ALA did not show any enhancement of fingermarks.

Effective fingerprint recognition technique using doped yttrium aluminate nano phosphor material

First time the yttrium aluminate nanoparticles are used to improve the fingerprint quality. Eco-friendly green combustion process is used to synthesize YAlO3:Sm3+ (0.5–11mol%) nanophosphor using green tea leaf extract as non-toxic and eco-friendly fuel. Powder X-ray diffraction study confirms the orthorhombic phase. The average sizes of the crystallites were found to be in the range 20–35nm. The emission peaks centered at 564, 601 and 647nm is attributed to 4f–4f 4G5/2→6HJ=5/2,7/2,9/2 forbidden transitions of Sm3+ ions. Judd–Ofelt theory is applied to experimental data for providing qualitative support by determining J–O intensity parameters. The Commission International De I-Eclairage chromaticity co-ordinates are very close to National Television System Committee standard value of white emission (x=0.296, y=0.237). Further, correlated color temperature is found to be ∼11,900K. A simple, fast, highly sensitive and low-cost method for the detection and enhancement of fingermarks in a broad range of surfaces is developed and constitutes an alternative to traditional luminescent powders.

A preliminary investigation into the use of alginates for the lifting and enhancement of fingermarks in blood.

Recent studies have reported the use of alginate in the lifting and subsequent enhancement of footwear marks in blood. A study was set up to assess the use of such a method in the treatment of fingermarks in blood on a variety of porous, non-porous and semi-porous surfaces. Other variables included ageing of the fingermarks in blood and the application of chemicals prior to or post-alginate lifting. All different variations were compared to direct chemical treatment of the substrate. The results demonstrated that alginate is not compatible with certain substrates (e.g. glass and tile). On substrates that were compatible with alginate (e.g. fabric and paper), the enhanced fingermarks on the alginate cast and the enhanced fingermarks on the post-alginate substrates appeared, overall, inferior compared to direct chemical enhancement without the use of alginate. A further variation using water-based protein stains directly mixed with the alginate appeared to provide enhancement directly on the substrate as well as simultaneous lifting and enhancing the fingermarks in blood on the alginate cast.

An investigation into the enhancement of fingermarks in blood on fruit and vegetables

A number of studies have reported the successful enhancement of latent fingermarks on fruit and vegetables. A study was set up to identify the most effective technique for the enhancement of fingermarks in blood on various fruit and vegetables. The enhancement techniques targeted different components in blood and consisted of protein stains (e.g. acid black 1), peroxidase reagents (e.g. leuco crystal violet) and amino acid stains (e.g. ninhydrin). Different variables such as the ageing periods of the marks and a diminishing series were employed to assess the suitability and sensitivity of the enhancement techniques. Overall, the use of different protein stains appeared to be the most effective techniques for the enhancement of fingermarks in blood on fruit and vegetables. In addition, the aubergine and cucumber skins appeared to be the most responsive surface to the different chemical techniques during enhancement. On the contrary, little or no enhancement was achieved for fingermarks in blood on the nectarine fruit.

An investigation into the enhancement of fingermarks in blood on paper with genipin and lawsone

The abilities of two natural products, genipin and lawsone, to enhance blood contaminated fingermarks on papers of various porosities and colour were investigated and compared to the routinely used amino acid reagents, ninhydrin and 1,8-diazafluoren-9-one (DFO). Fingermarks in blood were deposited as a split depletion series on various paper types and colours for ageing periods of 6 weeks, 4 weeks, 2 weeks and 1 week before enhancement. The developed marks were observed under different lighting conditions, recorded and graded by way of attributing quantitative data to each series. Results indicated that while genipin showed some potential as a reagent for the enhancement of latent fingermarks, it displayed no suitability for the enhancement of fingermarks in blood on paper. Lawsone also failed to successfully enhance either type of fingermark. Upon comparison of the results with those of ninhydrin and DFO it was found that ninhydrin displayed the highest success rate of development of these marks.