Evaluation of 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione for the detection of latent fingerprints on porous surfaces

The ability of 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione to detect latent prints on porous surfaces, as compared to DFO and ninhydrin, has been evaluated. Comparisons of prints developed under various conditions determined the optimum development conditions for the new reagents. The indanediones tested were found to have lower detection limits for glycine. The carrier solvent used was found to affect the quality of the prints developed. In Arklone, the new reagents developed prints that displayed superior luminescence to those developed with DFO. In HFE 7100, 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione gave superior luminescence to DFO after zinc salt treatment and cooling with liquid nitrogen, both of which improve the luminescence of prints developed with 1,2-indanediones. 1,2-Indanediones could offer less expensive but effective alternatives to DFO. With further optimization, the new reagents may supersede DFO as the method of choice for the detection of latent fingerprints on porous surfaces.     

A further study to investigate the detection and enhancement of latent fingerprints using visible absorption and luminescence chemical imaging

This study investigated the application of chemical imaging to the detection of latent fingerprints using the Condor macroscopic chemical imaging system (ChemImage Corp., Pittsburgh, USA). Methods were developed and optimised for the visualisation of untreated latent fingerprints and fingerprints processed with DFO, ninhydrin, cyanoacrylate, and cyanoacrylate plus rhodamine 6G stain. The results obtained with chemical imaging were compared to the detection achieved using conventional imaging techniques. The Condor significantly improved the detection of many prints, especially those that might be considered poor quality or borderline prints. Prints on newspaper treated with ninhydrin and DFO, and prints on white and yellow paper treated with ninhydrin, benefited the most from chemical imaging detection. In many cases, fingerprints undetectable using conventional imaging techniques could be visualised with chemical imaging. Ridge detail from untreated prints on yellow paper was also detected using the Condor. When prints of high quality were examined, both detection techniques produced quality results. The results of this project demonstrate that chemical imaging offers advantages over conventional visualisation techniques when examining latent fingerprints, especially those that would be considered difficult, such as weak prints or prints on surfaces that produce highly luminescent backgrounds. Standard testing procedures for the detection and enhancement of fingerprints by chemical imaging are presented and discussed.     

Development of latent fingerprints on compact disc and its effect on subsequent data recovery

Chance fingerprints may be found on every type of surfaces of contact and when they are latent, need to be developed by various methods. The type of surface on which latent prints are to be developed is one of the important factors when a choice for a method of development is to be made. The matter becomes more crucial when the surface is unique like a compact disc containing digital data. In this case, to develop the fingerprints is not the only matter to be taken care of but also, is very important to select such a method which may not effect the stored data and its retrieval. In present investigation, various methods have been tried to develop fingerprints on the writing surface of a CD and results are discussed with respect to their development as well as its effect on stored data and data retrieval.     

TFD-2纸张手印快速显现系统的应用

目的介绍一种利用特殊的红外热成像技术显现常见纸张上汗潜手印的新方法。方法利用英国Foster4-Freeman公司生产的TFD-2纸张手印快速显现系统,通过特殊的红外热成像技术,使汗潜手印呈现强烈荧光,从而显现手印。结果红外热成像方法处理后,汗潜手印在特种激发光（带宽为450nm-510nm）激发下显出较强的橙色荧光;持续处理后,汗潜手印在自然光下呈棕褐色,并在短波紫外光源（254nm）激发下也可显出清晰连贯的手印纹线;而且,新鲜和陈旧手印均有较好的显现效果。结论TFD-2纸张手印快速显现系统显现纸张上汗潜手印的方法,具有操作简单、快速安全、无需化学试剂、显现效果明显的特点,适合推广使用。     

Über Methoden zur Darstellung von latenten Fingerabdrücken auf der menschlichen Haut

Five methods are described for the detection of latent fingerprints on human skin: the X-ray method, the application of laser radiation, the iodine-silver plate transfer method, development with iron powder and Dakty-foil, as well as the photographic paper lift technique. Experiences with the application of these methods in forensic investigations are reported, and impeding factors are outlined. The simpler methods (the detection of such prints with iron powder and Dakty-foil as well as the photographic paper lift technique) are to be preferred for the investigation at the scene of the crime.     

Luminous lip-prints as criminal evidence

Luminescence is specially a useful property for the search of invisible evidences at the scene of a crime. In the latent fingerprints particular case, there are at one's disposal fluorescent reagents for their localization. The study of latent lip prints (that is lip prints from protective lipstick, or permanent or long-lasting lipstick that do not leave any visible marks) is more recent than fingerprints study. Because of the different composition of both types of prints, different reagents have been tried out on their developing. Although, lysochromes are particularly useful reagents to obtain latent lip prints, it may occur on coloured or multicoloured surfaces, the developing is not perceived due to contrast problems between the reagent and the surface where the print is searched. Again, luminescence offers the possibility to solve this problem. Nile Red is being studied as a potential developer for latent lip prints. The results on very old prints (over 1year) indicate that this reagent is highly efficient to get latent lip prints.     

胶带粘面手印荧光显现剂的研发与应用

目的根据胶带粘面上潜在手印的特点,利用染料和潜手印的理化性质,研究开发胶带粘面手印荧光显现剂。方法在各种胶带粘面上显现潜在手印,并与常规的碳素墨水染色法进行比较。结果在长波紫外线照射下手印呈黄色明亮荧光,手印纹线清晰、连贯,基本不受手印遗留时间、客体表面颜色和性质的影响。结论胶带粘面上的汗潜手印和血潜手印用荧光显现剂显现效果优于碳素墨水染色法,在实际案件的侦破中有较好的应用前景。     

Luminescent visualization of latent fingerprints by direct reaction with a lanthanide shift reagent.

The utilization of the lanthanide shift reagent tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium (III) [Eu(fod)3] as a simple one-step reagent for the luminescent visualization of latent fingerprints has been investigated. UV excitation of Eu(fod)3-treated prints, achieved by using a hand-held UV lamp or a Polilight, results in an orange emission at 614 nm. Time-resolved imaging is not required for visualization. Visualization of latent fingerprints on paper under the conditions used, although good, was found to be inferior to that obtained by standard DFO (1,8-diazafluoren-9-one) treatment, whereas visualization of prints obtained on aluminum drink cans and galvanized iron proved superior to that obtained by Superglue/panacryl treatment. Eu(fod)3 treatment can also be used first without compromising subsequent ninhydrin or DFO treatment, making it a 'nothing-to-lose" reagent.     

溴甲酚绿与溴甲酚蓝显现液显现潜血印痕的比较

目的 探索一种犯罪现场上潜血印痕新型显现技术；方法 利用溴甲酚绿、溴甲酚蓝、四丁基碘化铵与酒精溶液作为新型潜血印痕显现液,研究该技术显现潜血印痕的效果,并与国内外最常用的四甲基联苯胺显现技术进行交叉比较；结果 新型溴甲酚绿和溴甲酚蓝酒精显现液对稀释浓度到为1/1000的潜血印痕的极其敏感,显现出的手印纹线清晰连贯、反差明显,无颜色背景,且能够有效增强四甲基联苯胺处理后潜血印痕；结论 新型潜血印痕显现技术反应灵敏、反差明显,能作为四甲基联苯胺的后处理试剂,若得到推广应用,将能够有效提高犯罪现场上潜血印痕的发现率、提取率和利用率.     

The use of liquid latex as a pre-treatment to recover debris-covered latent fingerprints from exterior surfaces of vehicles

This study evaluated the effectiveness of using liquid latex as a pre-treatment for fingerprint recovery from the exterior surfaces of vehicles in summer. The sample of this study was 540 sebaceous latent fingerprints deposited on the lower body of three vehicles. Thirty control and thirty experimental fingerprints were deposited on each vehicle, and the experiment was repeated three times. The three vehicles were driven daily for either 2, 3, or 4 weeks after the deposition of fingerprints. After the vehicles reached their designated debris accumulation duration, the latent fingerprints in the control groups were developed with black fingerprint powder. Liquid latex was applied onto the fingerprints in the experimental groups, and they were subsequently developed with black fingerprint powder. A chi-sure test indicated that there was a significant difference in fingerprints recovery performance between two methods (X² = 4.903, d.f. = 1, p = 0.027). An odds ratio test indicated the control method increases the probability of fingerprint recovery by 1.54 times. A Fisher's exact test was used to evaluate the quality of fingerprints recovered from both methods and it indicated that there is no significant difference in quality using the two methods (p = 0.058). This study indicated that the traditional fingerprint powder method performed better for fingerprint recovery from exterior surfaces of vehicles in summer.     

Detection of visible and latent fingerprints using micro-X-ray fluorescence elemental imaging

Using micro-X-ray fluorescence (MXRF), a novel means of detecting fingerprints was examined in which the prints were imaged based on their elemental composition. MXRF is a nondestructive technique. Although this method requires a priori knowledge about the approximate location of a print, it offers a new and complementary means for detecting fingerprints that are also left pristine for further analysis (including potential DNA extraction) or archiving purposes. Sebaceous fingerprints and those made after perspiring were detected based on elements such as potassium and chlorine present in the print residue. Unique prints were also detected including those containing lotion, saliva, banana, or sunscreen. This proof-of-concept study demonstrates the potential for visualizing fingerprints by MXRF on surfaces that can be problematic using current methods.     

Processes involved in the development of latent fingerprints using the cyanoacrylate fuming method

Chemical processes involved in the development of latent fingerprints using the cyanoacrylate fuming method have been studied. Two major types of latent prints have been investigated-clean and oily prints. Scanning electron microscopy (SEM) has been used as a tool for determining the morphology of the polymer developed separately on clean and oily prints after cyanoacrylate fuming. A correlation between the chemical composition of an aged latent fingerprint, prior to development, and the quality of a developed fingerprint has been observed in the morphology. The moisture in the print prior to fuming has been found to be more important than the moisture in the air during fuming for the development of a useful latent print. In addition, the amount of time required to develop a high quality latent print has been found to be within 2 min. The cyanoacrylate polymerization process is extremely rapid. When heat is used to accelerate the fuming process, typically a period of 2 min is required to develop the print. The optimum development time depends upon the concentration of cyanoacrylate vapors within the enclosure.     

Fingerprints' third dimension: the depth and shape of fingerprints penetration into paper--cross section examination by fluorescence microscopy

In an attempt to maximize the yield of latent fingerprints from paper items, we conducted a study of a fundamental process between fingerprint deposits and paper. Fingerprint ridges have been observed in the cross section of paper by fluorescence microscopy. It was possible to see, for the first time, how residue from fingerprint ridges is embedded in paper. Undeveloped, latent fingerprints, as well as latent prints developed by the two fluorogenic reagents, DFO and 1,2-indanedione, have been examined. The shape and depth of penetration of fingerprints vary with different types of paper. An inverse relationship between the smoothness of the paper and the penetration depth was observed: higher smoothness values result in lower depths of penetration. High quality prints appear to correlate with an optimal penetration depth-between 40 and 60 microns.     

Doped hydrophobic silica nano- and micro-particles as novel agents for developing latent fingerprints

Novel hydrophobic silica based particles have been developed to visualise latent fingerprints. The composition of the particles has been designed to maximise both hydrophobic and ionic interactions between a variety of coloured and fluorescent reporter molecules and the silicate backbone within the particles. The resulting doped particles retain the incorporated dyes with high affinity. In addition, a variety of sub-particles have also been embedded to again produce coloured or magnetisable hydrophobic particles. The particles can be harvested as nanoparticles or microparticles. The former are applied to latent fingerprints as an aqueous suspension and the latter as a dusting agent using brushes or a magnetic wand. Examples of the prints produced using these agents are given. The resulting prints have good definition.     

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.     

Ridge Width Correlations between Inked Prints and Powdered Latent Fingerprints

A methodology to estimate the time of latent fingerprint deposition would be of great value to law enforcement and courts. It has been observed that ridge topography changes as latent prints age, including the widths of ridges that could be measured as a function of time. Crime suspects are commonly identified using fingerprint databases that contain reference inked tenprints (flat and rolled impressions). These can be of interest in aging studies as they provide baseline information relating to the original (nonaged) ridges’ widths. In practice, the age of latent fingerprints could be estimated following a comparison process between the evidentiary aged print and the corresponding reference inked print. The present article explores possible correlations between inked and fresh latent fingerprints deposited on different substrates and visualized with TiO₂. The results indicate that the ridge width of flat inked prints is most similar to fresh latent fingerprints_, and these should be used as the comparison standard for future aging studies.     

DFO／PVP试剂显现热敏纸上汗潜指纹方法研究

目的建立热敏纸上汗潜手印显现的新方法。方法根据DFO／PVP溶液能够阻碍热敏纸的显色,能够和手印遗留物质中的氨基酸发生显色反应的原理来显现手印。结果PVP浓度为5％、7．5％、10％时,荧光效果较好;DFO／PVP试剂显现热敏纸上汗潜指纹不会导致背景变黑;DFO／PVP试剂在热敏纸上的显现效果优于DFO试剂;对遗留时间为154天的ATM机上一枚凭证显出了清晰的指纹纹线。结论DFO／PVP显现法操作简单、安全可靠、显出率高、荧光强。     

A preliminary investigation into the acquisition of fingerprints on food

The potential for enhancement and recovery of latent fingerprints on a variety of foodstuffs has been investigated. In general, black magnetic powder and black powder suspensions appear to be the most successful enhancement techniques with a high number of ridge detail-developed prints over a selected time scale. Banana, apple and tomato surfaces showed enhancement of latent prints but potato and egg surfaces proved to be less successful.     

茚三酮固体介质法显现不同纸张表面潜指纹

茚三酮是显现渗透性客体上潜在汗液手印的最常用方法之一,采用微量物证提取纸和茚三酮溶液有机结合制作的茚三酮固体介质可以有效避免客体表面背景着色,不容易引起纸张油墨扩散,另外避免使用的溶剂易燃。能够更便捷的显现现场指纹,并且能够突破茚三酮只能显现渗透性客体的局限,拓宽茚三酮显现客体的范围,在热敏纸上潜指纹的显现方面有独特的应用优势。