Techniques for fingerprint recovery on vegetable and fruit surfaces used in Slovenia — A preliminary study

An examination was conducted to investigate whether certain dactyloscopic powders and reagents can recover latent fingerprints on vegetable and fruit surfaces (apple, banana, tomato and potato). Two fingerprint powders, Swedish Soot powder mixture (Swedish Black), Silver Special powder and cyanoacrylate fuming (CA), were investigated. The results have shown that detection with Swedish blackpowder is the most suitable procedure as the percentage finger marks which were of adequate quality for further examination, was higher than with any other technique examined.     

Development of a GC-MS method for the simultaneous analysis of latent fingerprint components

Latent fingerprint residue is a complex mixture of organic and inorganic compounds. A full understanding of the composition of this mixture and how it changes after deposition is lacking. Three solvent systems were compared for the simultaneous extraction and derivatization with ethyl chloroformate of selected amino and fatty acids from a nonporous substrate (Mylar for subsequent analysis by gas chromatography-mass spectrometry. A solvent system comprised of sodium hydroxide, ethanol, and pyridine was found to be the most effective. This method was applied to the analysis of latent fingerprint residue deposited on Mylar and preliminary data are presented. Twelve amino acids (e.g., serine, glycine, and aspartic acid) and 10 fatty acids (e.g., tetradecanoic, hexadecanoic, and octadecanoic acids) were identified. The potential application of this method to further the understanding of latent fingerprint chemistry has been demonstrated.     

群青悬浮液显现手印的研究

目的确定群青小颗粒悬浮液显现手印的最佳配方及适用范围;方法配置群青小颗粒悬浮液的不同浓度,对不同种类手印、不同时间手印以及不同客体上的手印进行试验显现;结果以1‰的1227表面活性剂水溶液为分散剂、浓度为20%的群青悬浮液为最佳配方;结论本研究结果可用于光滑非渗透性客体上遗留时间较短的多种物质手印的显现。     

纸张上潜在手印三种前处理方法对DNA检验的影响

目的通过比较常见纸张上潜在手印盲提法与显现后精准提取法的接触DNA检出率,探讨常见纸张上接触DNA前处理的优选方案。方法比较五种常见纸张上使用盲提法和显现潜在手印(茚二酮显现法、茚三酮熏显法)后精准提取法采集的接触DNA样本检出率。结果粗糙日历纸盲提的接触DNA检出率为17.8%,通过茚二酮法和茚三酮法显现的潜在手印所提取的DNA检出率分别为75.6%、77.8%;光滑日历纸三种方法所提取的接触DNA检出率为4.4%、11.1%、11.1%;A4复印纸三种方法接触DNA检出率为20%、37.8%、66.7%;牛皮纸三种方法接触DNA检出率为20%、68.9%、64.4%;快递纸袋的三种方法接触DNA检出率为2.2%、6.7%、46.7%。结论不同纸张上潜在手印经显现后接触DNA检出率不同,通过茚二酮或茚三酮显示潜在手印后精准提取DNA的前处理方法相较于盲提法的接触DNA检出率高。实战中可应用此类方法同时获得手印与DNA分型,以有效提高证据力。     

血手印显现的实验研究

目的 提出了采用荧光显现试剂显现血手印的新方法。方法 在比较使用联苯胺及其衍生物显现血手印的同时,实验了通过强氧化剂破坏血红素、沉淀珠蛋白,采用激活血痕、蛋白染色的方法,使血手印清晰显出。结果 显现效果不受客体表面颜色的影响,不受血手印遗留时间的影响。结论 适用客体范围广,灵敏度高。     

Effects of storage time on DNA profiling success from archived latent fingerprint samples using an optimised workflow

Due to recent improvements in forensic DNA testing kit sensitivity,there has been an increased demand in the criminal justice community to revisit past convictions or cold cases.Some of these cases have little biological evidence other than touch DNA in the form of archived latent fingerprint lift cards.In this study,a previously developed optimised workflow for this sample type was tested on aged fingerprints to determine if improved short tandem repeat(STR)profiles could be obtained.Two-year-old samples processed with the optimised workflow produced an average of approximately five more STR alleles per profile over the traditional method.The optimised workflow also produced detectable alleles in samples aged out to 28 years.Of the methods tested,the optimised workflow resulted in the most informative profiles from evidence samples more representative of the forensic need.This workflow is recommended for use with archived latent fingerprint samples,regardless of the archival time.     

汗潜指印DNA提取方法的初步研究

目的建立渗透性载体及非渗透性载体上汗潜指印DNA的提取和检验方法。方法采用C-有-柱法及SiO2法两种DNA提取方法,PCR扩增后310型遗传分析仪检测。结果载玻片上3枚汗潜指印采用2种方法均可扩增出Amel及9个STR位点;纸上3枚汗潜指印用SiO2法检见Amel及9个STR位点,而用C-有-柱法检验结果不稳定。渗透性及非渗透性载体上1及2枚汗潜指印,采用上述两种DNA提取方法,检验结果均不稳定。结论所建立的方法可以检见渗透性及非渗透性载体上汗潜指印DNA,并达到同一认定的程度。     

Determination of the hand from single digit fingerprint: a study of whorls

In this investigation 400 bilateral rolled fingerprints of Punjabi Jat males have been examined for the determination of the hand from single digit fingerprint from whorl patterns. Direction of the flow of the apex ridges, rotation of centrally circular ridges, angles between the core and the delta, ridge tracing, ridge counting and the position of the perpendiculars drawn between the delta and the core are useful for establishing in most of the cases the hand and finger involved from the fingers having whorl pattern.     

胶带的红外光谱检验

目的建立胶带的种类检验、方法。方法应用傅利叶显微红外光谱仪,分别对胶带的胶质、基质(基材)及整体(胶质和基质同时存在)进行检测分析。结果不同种类胶带,红外吸收图谱存在差异,相互间图谱匹配率不同。通过比对分析,可对不同种类的胶带进行鉴别。结论该方法检验胶粘带(胶带),检材用量少、结果准确,操作简便,具有很强的实用性。     

A new method of reproduction of fingerprints from corpses in a bad state of preservation using latex

In view of the problems arising while fingerprinting corpses in a bad state of preservation, especially in case of mummification and carbonization, the authors propose an innovative technique which uses latex film. To better illustrate the potential of the method, two cases where the latex technique was applied successfully are reported: the first one is a mummified body discovered in a shack on the outskirts of Milan and the second one is the case of a burnt corpse found in a car boot. Such a technique is versatile, easy to apply, and allows the operator to work quickly on cadavers without amputating parts, except in rare cases (i.e., burnt bodies with muscle retraction). By the latex technique, a perfect and enduring negative copy of the fingerprint is obtained, ready to be inked and photographed. The numerous copies produced this way can be inked several times allowing for the repeatability of the procedure and this is crucial in cases of problematic legal identification of corpses. In both the cases illustrated, the fingerprints obtained by the latex technique were useful for identification. The quality was good enough for the automatic fingerprint identification system research system to be applied.     

Toward multidimensional information: A derivatization-free UHPLC-QqQ MS/MS method for amino acid components of fingerprint

The analysis of fingerprint chemical composition is a meaningful way to excavate the multidimensional information of fingerprint, including the donor profiling information and the age of a fingerprint, which broadens the evidential values of fingerprint, especially for the partial and distorted fingerprint. But the research remains still in the pilot phases or is ongoing. Amino acids are the dominant organic substances in latent sweat fingerprint and influenced by many donor factors. Hence, their content reflects personal information of donors. Forensic science will be revolutionized if suspects can be individualized by their amino acid content. The diverse nature, distinct physicochemical properties, and ultra-micro levels of amino acids present in fingerprints make it hard to detect. A high sensitivity method for detecting and quantifying multiple amino acid components is required. UHPLC-QqQ MS/MS offers high sensitivity, high separation, simultaneous multicomponents detection, and no derivatization, making it an ideal method for detecting and analyzing amino acids in fingerprints. Therefore, in this study, we propose and validate an efficient UHPLC-QqQ MS/MS method for the extraction and analysis of 13 amino acids from fingerprint. We compared the results of amino acids of 10 different substrates and found that the inherent amino acids in most porous substrates would have been extracted along with the fingerprint amino acids, making them unsuitable for quantitative amino acid analysis. Instead, plastic sheets are ideal substrates for laboratory studies. Then, extensive experiments were conducted among 30 donors for multidimensional information analysis. The type of samples analyzed were eccrine-rich fingerprints. A Binary Logistic Regression (BLR) model was developed, and the female and male donors were successfully differentiated by amino acids in fingerprints. Two other mathematical models were also developed to verify the accuracy, and all three different mathematical models were able to identify donors of different genders with over 90% accuracy. This demonstrates that amino acids have the potential to provide more information for donors as metabolic markers. In the future, we will conduct a series of experiments to analyze more multidimensional information for individual identification by amino acid content in the fingerprint.     

The application of infrared chemical imaging to the detection and enhancement of latent fingerprints: method optimization and further findings

Fourier transform infrared (FTIR) chemical imaging allows the collection of fingerprint images from backgrounds that have traditionally posed problems for conventional fingerprint detection methods. In this work, the suitability of this technique for the imaging of fingerprints on a wider range of difficult surfaces (including polymer banknotes, various types of paper, and aluminum drink cans) has been tested. For each new surface, a systematic methodology was employed to optimize settings such as spectral resolution, number of scans, and pixel aggregation in order to reduce collection time and file-size without compromising spatial resolution and the quality of the final fingerprint image. The imaging of cyanoacrylate-fumed fingerprints on polymer banknotes has been improved, with shorter collection times for larger image areas. One-month-old fingerprints on polymer banknotes have been successfully fumed and imaged. It was also found that FTIR chemical imaging gives high quality images of cyanoacrylate-fumed fingerprints on aluminum drink cans, regardless of the printed background. Although visible and UV light sources do not yield fingerprint images of the same quality on difficult, nonporous backgrounds, in many cases they can be used to locate a fingerprint prior to higher quality imaging by the FTIR technique. Attempts to acquire FTIR images of fingerprints on paper-based porous surfaces that had been treated with established reagents such as ninhydrin were all unsuccessful due to the swamping effect of the cellulose constituents of the paper.     

自制炸药包壳的爆炸规律研究

目的探讨同种材质的包壳受到不同量的炸药爆炸后的物理损坏程度及分布规律。方法采用相同材质包壳、不同质量的硝铵（密度0.6g/cm3）若干份进行实验,根据炸药质量和密闭塑料瓶包壳体积的比值（相对密度）建立横坐标,不同直径碎片质量为纵坐标做出工作曲线。结果在固定体积下的特定塑料包壳中,10g~30g硝铵炸药爆炸后,包壳碎片质量与炸药量存在一定的规律。结论本方法可用于推算一定范围内自制炸药爆炸的药量。     

防止茚三酮溶液扩散纸张字迹的研究

目的 解决茚三酮溶液在显现手印同时对纸张上字迹产生扩散作的问题;方法 分别采用茚三酮丙酮溶液,茚三酮氟利昂溶液,茚三酮石油谜溶液,茚三酮庚烷溶液作比较。结果 钢笔字迹用4种溶液均不易扩散;纸张上其它成份字迹用后两种方法显现手印时可有效保存纸张上文字原貌。     

Amino acid alanine reactivity with the fingerprint reagent ninhydrin. A detailed ab initio computational study

Ninhydrin is one of the most widely used reagents for chemical development of fingerprints on porous surfaces. The detection is based on the reaction of ninhydrin with a monoacidic component of the fingerprint to form an intensively colored compound named Ruhemann's Purple. A computational study of the mechanisms and reaction energetics of the formation of Ruhemann's Purple from ninhydrin and alanine is presented. Such a study is significant from a forensic science point of view because of the strong interest in the forensic chemistry and law enforcement communities in developing alternatives to the current generation of ninhydrin like chemicals for the detection and development of latent fingerprints. Information about the mechanism of reaction between ninhydrin and amino acids can ultimately help to design compounds with stronger chromo-fluorogenic properties in aid of detecting fingerprints at crime scenes. The three most accepted mechanisms of formation have been considered using ab initio quantum mechanical calculations. At relatively high temperature ( approximately 100 degrees C) all three mechanisms are energetically feasible. However since it is recommended that forensic analyses be performed at room temperature, a revised mechanism is proposed for the formation of Ruhemann's Purple under this condition.     

A retrospective comparative study to evaluate the reliability of post-mortem interval sources in UK and US medico-legal death investigations

Post-mortem interval (PMI) information sources may be subject to varying degrees of reliability that could impact the level of confidence associated with PMI estimations in forensic taphonomy research and in the practice of medico-legal death investigation. This study aimed to assess the reliability of PMI information sources in a retrospective comparative analysis of 1813 cases of decomposition from the Allegheny County Office of the Medical Examiner in Pittsburgh, US (n = 1714), and the Crime Scene Investigation department at Southwest Forensics in the UK (n = 99). PMI information sources were subjected to a two-stage evaluation using an adapted version of the 3x5 aspects of the UK police National Intelligence Model (NIM) to determine the confidence level associated with each source. Normal distribution plots were created to show the distribution frequency of the dependent variables (decomposition stage and source evaluation) by the independent variable of PMI. The manner, location, and season of death were recorded to ascertain if these variables influenced the reliability of the PMI. A confidence matrix was then created to assess the overall reliability and provenance of each PMI information source. Reliable PMI sources (including forensic specialists, missing persons reports, and digital evidence) were used across extensive PMI ranges (1 to 2920 days in the US, and 1 to 240 days in the UK) but conferred a low incidence of use with forensic specialists providing a PMI estimation in only 35% of all homicide cases. Medium confidence PMI sources (e.g., last known social contact) accounted for the majority of UK (54%, n = 54) and US (82%, n = 1413) cases and were associated with shorter PMIs and natural causes of death. Low confidence PMI sources represented the lowest frequencies of UK and US cases and exclusively comprised PMI information from scene evidence. In 96% of all cases, only one PMI source was reported, meaning PMI source corroboration was overall very low (4%). This research has important application for studies using police reports of PMI information to validate PMI estimation models, and in the practice of medico-legal death investigation where it is recommended that i) the identified reliable PMI sources are sought ii) untested or unreliable PMI sources are substantiated with corroborating PMI information, iii) all PMI sources are reported with an associated degree of confidence that encapsulates the uncertainty of the originating source.     

A rapid microtechnique for the detection of trace metals from gunshot residues.

The most important facts and advantages of this method are as follows. 1. A simple separation and identification scheme for metals considered characteristic of gunshot residues was developed. 2. The apparatus used is inexpensive, simple, extremely versatile, and has moderate sensitivity. 3. Blanks of background ions present do not interfere with the test, but warrant consideration. 4. Few reagents are needed, and the results are preservable.     

指甲花醌显现纸张上汗潜手印初步研究

目的介绍一种用天然植物提取成分指甲花醌显现渗透性纸张表面汗潜手印的方法。方法利用指甲花醌能够和手印遗留物质中的氨基酸发生显色反应来显现手印。结果显现出的手印纹线在自然光下观察呈紫褐色,并且在540nm激发光源条件下,通过红色护目镜观察还有很强的荧光特征。结论指甲花醌显现法具有安全性高、健康环保、操作简单、显现效果明显的特点。     

A mechanistic model for the superglue fuming of latent fingerprints

The use of superglue vapors to detect latent fingerprints, known as superglue fuming, is a chemical process that has not been fully described. The role of the fingerprint material in the process, leading to formation of methyl cyanoacrylate polymer at the site of the fingerprint, remains to be established. Films of liquid alkanes respond similarly to actual fingerprints in the fuming experiment. Their responses depended on the hydrocarbon used, viscosity, and film thickness. Aspects such as film thickness appear to be relevant for actual fingerprints as well. A model was proposed in light of these observations. The model compares the process with gas chromatography, in which molecules partition between the gas phase and a stationary phase. Aspects such as accumulation of superglue monomers by partitioning into a thin film (or wax) are consistent with the preferential response of fingerprints on surfaces relative to the background.