Upper‐Bounding the Incidence Rate of Associations Between Camouflage Uniforms and Surveillance Images*

Abstract: Camouflage garments can be associated with surveillance images of a crime scene even in the absence of unique wear marks or very high‐quality images. However, the probability of an accidental association, or incidence rate, is significant. The present work describes and validates a method for estimating the incidence rate based on a statistical model of the garment manufacturing process. The model was developed primarily for use with the current U.S. Army Combat Uniform (ACU), but can be applied to any camouflage garment. Eight garment manufacturers were studied, and all sources of variation in the manufacturing process were characterized. The marking and spreading procedures were found to be dominant and consistent sources of variation. However, some sources of variation, in particular those because of human operators, were not consistent enough to accurately characterize. Sources of variation that could not be well‐characterized were ignored in the statistical model, yielding a worst‐case estimate that is an upper‐bound to the true incidence rate. The model was evaluated for a variety of cases. Depending on the quality of the surveillance image, the manufacturing parameters, and the local population, incidence rates range from about 3% to negligibly small. The model was validated by returning to one manufacturer, and sampling a large number of completed garments and estimating empirical match probabilities. The empirical probabilities validated the estimates of the worst‐case incidence rate and also demonstrated that typical incidence rates are significantly lower.     

The reincorporation and redistribution of trace geoforensic particulates on clothing: An introductory study

Two experimental studies were undertaken to investigate the processes of reincorporation and redistribution of trace evidence on garments when worn by a suspect or a victim (reincorporation) or after the garments have been seized and packaged for subsequent forensic analysis (redistribution). The first experiment utilised UV powder, an established proxy for geoforensic trace particulates and the second experiment utilised daffodil pollen transferred onto garments under conditions that mimicked forensic reality. It was demonstrated that reincorporation of trace particulates occurs from upper to lower parts of the same garment and also from upper garments to lower garments. Reincorporation also occurred to all areas of the lower garments, however the highest concentration of particulates was found to be the lap area of the jeans. Particulates also tended to be preserved around technical details such as stitching or relief design features of the garments. Thus the decay of particulates after a contact has been made does not necessarily involve a loss of those particulates from the entire system. These findings have implications for the interpretation of trace evidence when seeking to establish the source of initial contacts or the chronology of pertinent events. The second study demonstrated that folding and packaging items of clothing leads to a redistribution of any trace particulate evidence that is present thereby eliciting an alteration in the spatial distribution of that evidence. There is therefore a necessity to take the context of trace evidence into account and also to follow protocols that are sensitive to these aspects of trace evidence behaviour as a failure to do so may have consequences for the correct interpretation of such evidence.     

The discrimination of (non-denim) blue cotton

This study was conducted to determine the degree of discrimination obtained between non-denim blue cotton fibres using visible–UV range microspectrophotometry alone. To this end, samples of fibres were taken from 100, non-denim, blue cotton, outer garments, including t-shirts, trousers and jumpers and subjected to analysis by both visible and UV range microspectrophotometry. The results obtained from the samples of each garment were compared to determine if they ‘matched’ or not. From an initial visual comparison of the garments it was possible to subdivide the samples into two populations consisting of 73 ‘dark blue’ garments and 27 ‘mid-blue’ garments. It was found that of the 73 ‘dark blue’ garments, 22 distinct sub-populations could be distinguished using visible range MSP, this figure being increased to 43 when the analysis was extended into the UV range. In the case of the 27 ‘mid-blue’ garments, 9 distinct sub-populations were discriminated using visible range MSP, this figure being increased to 17 when the analysis was extended into the UV range. The discriminating power (i.e. the number of discriminated pairs divided by the number of possible pairs) of visible range microspectrophotometry was calculated as 0.89 for ‘mid-blue’ garments and 0.87 for ‘dark blue’ garments. Extending microspectrophotometry into the UV range increased discrimination by 7%, giving a discriminating power of 0.96 for both mid and dark blue cotton fibres which was similar to that reported by a previous study where this method was combined with light and fluorescence microscopy.Intra-garment variation was found to be negligible. The implications of this study for casework are discussed and a revised analytical pathway for the comparison of this fibre type/colour combination using microspectrophotometry as a primary screening tool, is proposed.     

反恐视角下穿着遮面长袍行为的法律规制——基于新疆地区的研究

遮面长袍并非维吾尔族的传统服饰。穿着遮面长袍的行为与宗教极端思想渗透密切相关,它危害社会稳定,侵蚀民族传统文化,侮辱妇女人格,违反男女平等原则。近年来,法国、比利时等国先后颁布了禁止在公共场所穿着遮面长袍的法律。为维护社会稳定,保障国家文化安全,防止宗教极端思想渗透,我国有必要借鉴法国、比利时等国的立法,由全国人大制定禁止在公共场所穿着遮面长袍的法律,违者由县级公安机关处以一定数额的罚款。     

The migration of fragments of glass from the pockets to the surfaces of clothing

During the last decade or so there has been some discussion in the forensic community in the United Kingdom concerning whether it is necessary to search the pockets for glass particles in garments attributed to suspects arrested for glass breaking crimes. The removal of this practice would help expedite the searching and recovery process since examining only the surfaces of clothing would reduce the cost of recovering glass evidence. However, it is believed by many scientists that some glass fragments originally acquired in pockets can migrate to the surfaces of clothing prior to examination by the forensic scientist. As glass fragments have been encountered in the pockets of garments during examinations of casework items in the LGC Laboratories, the implications of this change in practice needs to be assessed. Hence, the aim of this study was to investigate this possibility that fragments of glass migrate from a pocket of a garment to its surfaces during police and laboratory handling after a person is suspected of breaking glass during an offence. If this occurs to a significant extent then it could affect the evaluation of the glass evidence when using a Bayesian approach. Sixty fragments of glass were seeded into a pocket of a fleece jacket and a pair of denim jeans. Three experiments were performed; one examined a searching, recovery and blanking procedure, another examined the pre-laboratory 'handling' process of an item in an evidence bag, and the third experiment looked at the removal of an object from a pocket laden with glass and subsequent removal and packaging of the garment. Up to two (3.3%) fragments were recovered from the surfaces of the fleece jacket and the denim jeans via the searching, recovery and blanking procedure. Similar numbers were also recovered from the insides of the evidence bags. Up to four (6.7%) fragments were recovered from the surface of the fleece jacket and up to five (8.3%) fragments were recovered from the surface of the denim jeans after pre-laboratory 'handling'. Again similar numbers were recovered from the insides of the evidence bags. Comparable numbers to those from searching/recovery experiments were observed when garments were removed after taking an object from a pocket. In addition, up to two (3.3%) fragments were recovered from the object (a mobile phone). The findings show that some migration can occur particularly in the second experiment and therefore modification of the evaluation strategy may be required.     

A large study evaluation of evidence types containing offender fingerprints from recorded crimes in North Macedonia from 2005 to 2015

The Forensic Institute of the Republic of North Macedonia data set of 1,982 offender fingerprint identifications contributing to a conviction for crimes against property, was evaluated and analysed using contingency table statistical analysis techniques, chi-square test, fisher’s exact test and post hoc analysis. The data set was based on the forensic and court information available from 2005 to 2015 and pertained to the location, property type and evidence type. Interpretation of the data identified glass components, doors, windows, points of entry, cardboard and other packaging to be the most likely areas for locating offender fingerprints in non-residential and residential properties. In vehicle-based crimes, the front area (both left- and right-hand side) was the most likely to yield offender fingerprints.This study reinforced the types of evidential items at property based crime scenes yielding offender fingerprints. In addition, the study seeks to provide recommendations for future data collection to enhance the data analysis and interpretation.     

The showup identification procedure: An exploration of systematic biases

Purpose. Showups are common, yet little research has investigated the biasing factors that may influence showup identifications. We investigated the effects of cross‐race conditions and clothing bias on showup identification decisions. Additionally, we explored identification decisions made in a subsequent lineup dependent on race, clothing, and showup‐target‐presence. Methods. Participants watched a mock crime and were presented with a showup in which suspect race, target‐presence, and the clothing worn by the suspect were varied. Following a delay, participants viewed a target‐present or ‐absent lineup and were asked to make a second identification decision. Results. Presentation of the suspect in the clothing worn by the perpetrator increased choosing rates in both own‐race and other‐race conditions. Despite this, differential patterns of decision response latencies indicated that eyewitnesses may use clothing information differently when making own‐race compared to other‐race identification decisions. No evidence for an own‐race bias in showup identifications was found; however, other‐race lineup identifications were less accurate than own‐race lineup identifications. Further, participants in own‐race and other‐race conditions differed in the extent to which they were affected by multiple identification procedures. Viewing an own‐race innocent suspect in a showup increased subsequent false lineup identifications, while choosing the innocent suspect from the showup was necessary to increase false lineup identifications in other‐race conditions. Conclusions. Different situational factors may affect the identification accuracy of eyewitnesses in own‐race and other‐race conditions for both showup and lineup procedures. Particular caution is advised when showups are clothing‐biased and multiple identification procedures are used.     

患者死亡医疗纠纷司法鉴定24例分析

目的探讨涉及患者死亡医疗纠纷的过错成因,分析其司法鉴定的切入点。方法收集了涉及患者死亡且多次鉴定的医疗纠纷案例24例,从一般情况、科室分布、责任程度划分以及差错分析等方面进行了总结和分析。结果此类案例在技术方面存在患者自身疾病隐匿、接诊部门处理过程简单、科室之间配合不力、紧急情况下措施不果断等问题。此外,告知义务的履行、转诊时机把握以及常备抢救设施的维护等管理方面漏洞也是医疗纠纷的多发环节。结论本文可为进行此类医疗纠纷的司法鉴定提供帮助,也为避免纠纷的发生提供参考。     

Computer‐aided Dental Identification: An Objective Method for Assessment of Radiographic Image Similarity*

Abstract: A pilot study evaluated a computer‐based method for comparing digital dental images, utilizing a registration algorithm to correct for variations in projection geometry between images prior to a subtraction analysis. A numerical assessment of similarity was generated for pairs of images. Using well‐controlled laboratory settings, the method was evaluated as to its ability to identify the correct specimen with positive results. A subsequent clinical study examined longitudinal radiographic examinations of selected anatomical areas on 47 patients, analyzing the computer‐based method in making the correct identification based upon a threshold level of similarity. The results showed that at a threshold of 0.855, there were two false negative and two false positive identifications out of 957 analyses. Based on these initial findings, 25 dental records having two sets of full mouth series of radiographs were selected. The radiographs were digitized and grouped into six anatomical regions. The more recent set of films served as postmortem images. Each postmortem image was analyzed against all other images within the region. Images were registered to correct for differences in projection geometry prior to analysis. An area of interest was selected to assess image similarity. Analysis of variance was used to determine that there was a significant difference between images from the same individual and those from different individuals. Results showed that the threshold level of concordance will vary with the anatomical region of the mouth examined. This method may provide the most objective and reliable method for postmortem dental identification using intra‐oral images.     

Recovery of Trace DNA on Clothing: A Comparison of Mini‐tape Lifting and Three Other Forensic Evidence Collection Techniques

Trace DNA is often found in forensic science investigations. Experience has shown that it is difficult to retrieve a DNA profile when trace DNA is collected from clothing. The aim of this study was to compare four different DNA collection techniques on six different types of clothing in order to determine the best trace DNA recovery method. The classical stain recovery technique using a wet cotton swab was tested against dry swabbing, scraping and a new method, referred to as the mini‐tape lifting technique. Physical contact was simulated with three different “perpetrators” on 18 machine‐washed garments. DNA was collected with the four different DNA recovery methods and subjected to standard PCR‐based DNA profiling. The comparison of STR results showed best results for the mini‐tape lifting and scraping methods independent of the type of clothing. The new mini‐tape lifting technique proved to be an easy and reliable DNA collection method for textiles.     

DNA Typing for the Identification of Old Skeletal Remains from Korean War Victims*

Abstract: The identification of missing casualties of the Korean War (1950–1953) has been performed using mitochondrial DNA (mtDNA) profiles, but recent advances in DNA extraction techniques and approaches using smaller amplicons have significantly increased the possibility of obtaining DNA profiles from highly degraded skeletal remains. Therefore, 21 skeletal remains of Korean War victims and 24 samples from biological relatives of the supposed victims were selected based on circumstantial evidence and/or mtDNA‐matching results and were analyzed to confirm the alleged relationship. Cumulative likelihood ratios were obtained from autosomal short tandem repeat, Y‐chromosomal STR, and mtDNA‐genotyping results, and mainly confirmed the alleged relationship with values over 10⁵. The present analysis emphasizes the value of mini‐ and Y‐STR systems as well as an efficient DNA extraction method in DNA testing for the identification of old skeletal remains.     

A Novel Pixel‐Based Method to Estimate the Instantaneous Velocity of a Vehicle from CCTV Images

In traffic forensic identifications, it was usually unfavorable that estimated velocities of questioned vehicles derived from frame‐based methods eventually turned out to be close to but a bit less than speed limits. In this paper, a novel pixel‐based method was presented to estimate vehicles’ relatively instantaneous velocities. First, two adjacent pixels’ actual distance was acquired from the closed‐circuit television (CCTV) images. Then, the instantaneous average velocity within this one frame interval time (FIT) was calculated out. The frame‐based method and its evaluating result were also introduced in this paper. The results showed that the velocity estimated by this new pixel‐based method was higher than which derived from the frame‐based method. Employing this presented novel method in these cases, it could be more accurately identified whether or not the vehicles had exceeded the speed limits, and then the responsibilities could be consequently assigned impartially.     

Probative Value of Absolute and Relative Judgments in Eyewitness Identification

It is well-accepted that eyewitness identification decisions based on relative judgments are less accurate than identification decisions based on absolute judgments. However, the theoretical foundation for this view has not been established. In this study relative and absolute judgments were compared through simulations of the WITNESS model (Clark, Appl Cogn Psychol 17:629–654, 2003) to address the question: Do suspect identifications based on absolute judgments have higher probative value than suspect identifications based on relative judgments? Simulations of the WITNESS model showed a consistent advantage for absolute judgments over relative judgments for suspect-matched lineups. However, simulations of same-foils lineups showed a complex interaction based on the accuracy of memory and the similarity relationships among lineup members.     

A NEW METHOD FOR STUDYING THE EXTENT,STABILITY, AND PREDICTORS OF INDIVIDUAL SPECIALIZATION IN VIOLENCE*

Specialization in violence is an important scientific and policy topic, and over the past several decades, many analysis techniques for studying specialization have emerged. Research in this area continues to be hampered, however, by remaining methodological problems. To overcome these problems, we propose a new method for studying specialization in violence based on an item‐response theory measurement approach that is implemented through a multilevel regression model. Our approach defines specialization as an individual level latent variable, takes into account the inherent confounds between specialization and overall level of offending, and gauges specialization relative to the population base rates of each offense. Our method also enables researchers to 1) estimate the extent and statistical significance of specialization, 2) assess the stability of specialization over time, and 3) relate specialization to explanatory variables. Using data from three studies, we found substantial levels of specialization in violence, considerable stability in specialization over time, and several significant and relatively consistent relationships of specialization to explanatory variables such as gender, parental education, and risk‐seeking.     

A single approach to the recovery of DNA and firearm discharge residue evidence.

The Laboratory of the Strathclyde Police Forensic Support Department extracts DNA from cellular material recovered from garments submitted as evidence. The standard method used an adhesive tape attached to a plastic or acetate support. This paper demonstrates a method whereby a single sample, recovered from clothing, can be examined for Firearm Discharge Residue and then extracted for DNA.     

Further insights into the persistence of transferred fibres on outdoor clothes.

This study was conducted to assess persistence of fibres on items of outdoor clothes in normal wear situations. The persistence of acrylic and wool fibres transferred on 23 recipient garments was examined in relation to: time of wear; features of the recipient garment (fibre composition, surface structure and texture); conditions of wear (public transport used or not), and; their location on the recipient. After 8 hours of wear more than 75% of transferred fibres were lost during 8-10 hours of wear. After 16 hours of wear no more than 10%, most often up to 5%, of fibres remained. Fibres were lost at higher rate when public transport was used. The persistence of fibres depended more on the surface structure and texture of the recipient garment and the location of donor fibres rather than on the type of fibre.     

Analysis of Mitochondrial DNA from a Burned,Ninhydrin‐Treated Paper Towel

Contact‐based evidence is likely to have limited quantities of DNA and may yield mixed profiles due to preexisting or contaminating DNA. In a recent arson investigation, a paper towel was collected and used as circumstantial evidence. The paper towel was partially burned and was likely set on fire with flammable liquid. As part of the investigation, the paper towel was treated with ninhydrin to visualize fingerprint evidence. Initial DNA analysis of two swabs was negative for short tandem repeat (STR) markers and revealed a mixture of mitochondrial DNA (mtDNA). Analysis of 13 additional cuttings yielded four more mixed profiles, but also two samples with a common single‐source profile. The single‐source mtDNA profile matched that of the primary suspect in the case. Thus, even if initial mtDNA analysis yields a mixed profile, a sampling strategy involving multiple locations can improve the chance of obtaining valuable single‐source mtDNA profiles from compromised evidence in criminal casework.     

Comparison of the Volatile Organic Compounds from Different Biological Specimens for Profiling Potential*

Previous work has demonstrated the ability to differentiate individuals based on the analysis of human scent hand odor chemicals. In this paper, a range of forensic biological specimens are shown to also have the ability to differentiate individuals based upon the volatile organic compounds (VOCs) present. Human VOC profiles from hand odor, oral fluid, breath, blood, and urine of 31 individuals were analyzed by solid‐phase microextraction–gas chromatography–mass spectrometry (SPME‐GC‐MS) and combined methods of chromatogram comparison, Spearman rank correlation comparison, and principal component analysis. Intra‐specimen comparisons demonstrated the distinguishability of individuals above 99%. Inter‐specimen VOC profiles from the same individual were found to be too different to be used for scent‐matching purposes, with Spearman rank coefficients below 0.15. A 6‐month VOC profile monitoring of two individuals demonstrated the consistency of VOC profiles over time across specimens.     

Information‐Theoretical Assessment of the Performance of Likelihood Ratio Computation Methods

Performance of likelihood ratio (LR) methods for evidence evaluation has been represented in the past using, for example, Tippett plots. We propose empirical cross‐entropy (ECE) plots as a metric of accuracy based on the statistical theory of proper scoring rules, interpretable as information given by the evidence according to information theory, which quantify calibration of LR values. We present results with a case example using a glass database from real casework, comparing performance with both Tippett and ECE plots. We conclude that ECE plots allow clearer comparisons of LR methods than previous metrics, allowing a theoretical criterion to determine whether a given method should be used for evidence evaluation or not, which is an improvement over Tippett plots. A set of recommendations for the use of the proposed methodology by practitioners is also given.     

Sensitive Method for the Confident Identification of Genetically Variant Peptides in Human Hair Keratin

Recent reports have demonstrated that genetically variant peptides derived from human hair shaft proteins can be used to differentiate individuals of different biogeographic origins. We report a method involving direct extraction of hair shaft proteins more sensitive than previously published methods regarding GVP detection. It involves one step for protein extraction and was found to provide reproducible results. A detailed proteomic analysis of this data is presented that led to the following four results: (i) A peptide spectral library was created and made available for download. It contains all identified peptides from this work, including GVPs that, when appropriately expanded with diverse hair-derived peptides, can provide a routine, reliable, and sensitive means of analyzing hair digests; (ii) an analysis of artifact peptides arising from side reactions is also made using a new method for finding unexpected modifications; (iii) detailed analysis of the gel-based method employed clearly shows the high degree of cross-linking or protein association involved in hair digestion, with major GVPs eluting over a wide range of high molecular weights while others apparently arise from distinct non-cross-linked proteins; and (v) finally, we show that some of the specific GVP identifications depend on the sample preparation method.