Person identification by gait analysis and photogrammetry

Surveillance images from a bank robbery were analyzed and compared with images of a suspect. Based on general bodily features, gait and anthropometric measurements, we were able to conclude that one of the perpetrators showed strong resemblance to the suspect. Both exhibited a gait characterized by hyperextension of the leg joints, and bodily measurements did not differ by more than 6 mm on average. The latter was quantified by photogrammetry: i.e., measuring by using images of the perpetrator as captured by surveillance cameras. Using the computer software Photomodeler Pro, synchronous images from different cameras were compared and concurrent body features were identified. The program could then render the perpetrator as a three dimensional, high-precision, scalable and measurable object.     

A medical model for criminalistics education

The history of medical education during the period of 1870 to 1926 is examined in the context of current issues confronting education in the forensic laboratory sciences. Medical education was radically altered during this period, changing from a rudimentary lecture/apprenticeship system into its modern form. Although the motivating forces had developed over some time, the actual change was quite rapid. By examining how this change occurred, we gain insight into how changes in our own profession might be initiated. Parallels between our current situation and that in medical education 117 years ago include: (1) the primary burden of professional education is borne outside the university in an apprenticeship system, (2) the apprenticeship system is overburdened by a dramatic expansion in the knowledge and skills needed for professional practice, (3) there is no standardized curriculum or accreditation process for educational programs, and (4) there is no educational program that incorporates formal clinical education. Based on this historical analysis, three major goals are proposed: (1) active entreprenurial promotion of professional educational programs by academics, (2) creation of a committee within the American Academy of Forensic Sciences to critique and rate university programs, and (3) the development of a well-defined clinical education program. A model for formalized clinical education in the forensic laboratory sciences is proposed, incorporating clinical professors, student clerkships, and university control over instruction within an operational forensic science laboratory. Benefits from this arrangement include: efficient combination of physical plants, added personnel resources in the laboratory, rapid introduction of research into the laboratory, enhanced prestige for both academics and practitioners, and relief of the laboratory's in-house training burden.     

人体组织/体液来源的法医学鉴定

生物检材的组织/体液来源鉴定是法医学检验的重要内容之一。法医学组织/体液鉴定的方法较多,无论是基于酶促反应或免疫学检测的传统鉴定方法,还是光谱法或近年来基于mRNA、microRNA或DNA甲基化差异的分子生物学组织鉴定技术,均各有特点。本文就各种法医学组织/体液鉴定方法的特点及其法医学应用价值作一简要综述。     

The identification of individuals by observational gait analysis using closed circuit television footage

This study investigated the ability of individuals with experience in gait analysis to identify people by observing features of gait recorded by closed circuit television cameras (CCTV). Seven experienced analysts each viewed five samples of footage. Each sample showed a “target walker” and five “suspect walkers.” The task of the experienced analysts was to determine which, if any, of the “suspect walkers” was the “target walker.” All of the participant “walkers” wore identical loose fitting clothing to mask anatomical and body contour features, and balaclavas to obscure facial features. The overall results showed that the experienced analysts made a correct decision in 124 of 175 cases (71%), significantly better than would have been expected to have occurred by chance (p < 0.05). A significant variation in correct decisions (p < 0.05) was shown to occur between the various angles from which the footage was recorded, footage recorded in the saggital plane showing the highest number of correct decisions. Significantly more correct decisions (p < 0.05) were also shown to occur when the footage of the “target walker” and that of the “suspect walker” were taken from the same angle. The results suggest that individuals with experience in gait analysis perform well in the comparative identification of suspects from CCTV footage, and therefore do have a role to play as expert witnesses in this field.     

Forensic parasitology:a new frontier in criminalistics

Parasites are ubiquitous,diverse,and have close interactions with humans and other animals.Despite this,they have not garnered significant interest from forensic scientists,and their utility as indicators in criminal investigations has been largely overlooked.To foster the development of forensic parasitology we explore the utility of parasites as forensic indicators in five broad areas:(i)wildlife trafficking and exploitation,(ii)biological attacks,(iii)sex crimes,(iv)criminal neglect of humans and other animals,and(v)indicators of movement and travel.To encourage the development and growth of forensic parasitology as a field,we lay out a four-step roadmap to increase the use and utility of parasites in criminal investigations.     

The analysis of illicit methaqualone containing preparations by gas chromatography-mass spectrometry for forensic purposes

A validated gas chromatographic-mass spectrometric method for quantitative analysis of methaqualone (MTQ) in illicit preparations is reported. The method proved to have a coefficient of variation of below 5%. Four batches of seized tablets, two pairs with similar imprints, were analyzed. It was found that the average MTQ concentration in all four batches of tablets differed significantly (p = 0.01) rendering it impossible to conclude that, on the basis of MTQ concentration alone, the batches with a similar logo originated from the same manufacturer or manufacturing batch. Conversely, it can be said that in this case, the four batches originated from either different clandestine laboratories or manufacturing batches.     

Elemental analysis of soil samples for forensic purposes by inductively coupled plasma spectrometry--precision considerations

Major and trace elemental composition provides a powerful basis for forensic comparison of soils, sediments and rocks. However, it is important that the potential 'errors' associated with the procedures are fully understood and quantified, and that standard protocols are applied for sample preparation and analysis. This paper describes such a standard procedure and reports results both for instrumental measurement precision (repeatability) and overall 'method' precision (reproducibility). Results obtained both for certified reference materials and example soils show that the instrumental measurement precision (defined by the coefficient of variation, CV) for most elements is better than 2-3%. When different solutions were prepared from the same sample powder, and from different sub-sample powders prepared from the same parent sample, the CV increased to c. 5-6% for many elements. The largest variation was found in results for certified reference materials generated from 23 instrument runs over an 18 month period (mean CV=c. 11%). Some elements were more variable than others. W was found to be the most variable and the elements V, Cr, Co, Cu, Ni and Pb also showed higher than average variability. SiO2, CaO, Al2O3 and Fe2O3, Rb, Sr, La, Ce, Nd and Sm generally showed lower than average variability, and therefore provided the most reliable basis for inter-sample comparison. It is recommended that, whenever possible, samples relating to the same investigation should be analysed in the same sample run, or at least sequential runs.     

广州话语音声纹鉴定中的量化分析研究

本研究从一般元音(音节核心)的同一认定方法着手,着重从定量分析方面研究声学特征参量,把多元统计方法使用到声纹鉴定中。通过计算变异系数、相关系数、正态性检验、方差分析等基本统计分析,对于男性语音,制定了马氏距离判别数学模型,判对率达98.3%;对于女性语音,制定了费歇(Fisher)判别数学模型,判对率达93.5%。本研究解决了声纹鉴定对声学特征参量定量分析方面的问题,确定了判定阈值及鉴定所需音节数,提供了一种新的语音判别方法。     

The use of medical examinations for employment purposes

This article examines a number of legal issues which arise where medical examinations or tests are used in the employment context, either to test the suitability of a prospective employee in pre-employment situations or to ascertain the fitness of existing employees. Employer justifications for seeking medical information usually relate to attempts to comply with health and safety legislation and to reduce workers compensation costs. This article discusses the legal obligations involved in pre-employment medical testing and, in particular, employee obligations to provide correct information in relation to their health to a prospective employer. It also notes the consequences for employees of providing false information in relation to workers compensation claims and dismissal cases. The article notes the growing trend of requiring drug and alcohol testing for existing employees, particularly in the mining industry. The article concludes by noting that employers need to take care in seeking medical information, and that it should not simply be done as a mechanical, matter-of-course exercise. Failure to observe anti-discrimination laws may result in the employer facing allegations of misuse of medical information and claims for damages for discrimination.     

Headspace profiling of cocaine samples for intelligence purposes

A method for determination of residual solvents in illicit hydrochloride cocaine samples using static headspace-gas chromatography (HS-GC) associated with a storage computerized procedure is described for the profiling and comparison of seizures. The system involves a gas chromatographic separation of 18 occluded solvents followed by fully automatic data analysis and transfer to a PHP/MySQL database. First, a fractional factorial design was used to evaluate the main effects of some critical method parameters (salt choice, vial agitation intensity, oven temperature, pressurization and loop equilibration) on the results with a minimum of experiments. The method was then validated for tactical intelligence purposes (batch comparison) via several studies: selection of solvents and mathematical comparison tool, reproducibility and "cutting" influence studies. The decision threshold to determine the similarity of two samples was set and false positives and negatives evaluated. Finally, application of the method to distinguish geographical origins is discussed.     

Three-dimensional surface topography acquisition and analysis for firearm identification

In the last decade, computer-based systems for the comparison of microscopic firearms evidence have been the subject of considerable research work because of their expected capability of supporting the firearms examiner through the automated analysis of large amounts of evidence. The Integrated Ballistics Identification System, which is based on a two-dimensional representation of the specimen surface, has been widely adopted in forensic laboratories worldwide. More recently, some attempts to develop systems based on three-dimensional (3D) representations of the specimen surface have been made, both in the literature and as industrial products, such as BulletTRAX-3D, but fundamental limitations in achieving fully automated identification remain. This work analyzes the advantages and disadvantages of a 3D-based approach by proposing an approach and a prototype system for firearms evidence comparison that is based on the acquisition and analysis of the 3D surface topography of specimens, with particular reference to cartridge cases. The concept of 3D virtual comparison microscope is introduced, whose purpose is not to provide fully automated identification, but to show how the availability of 3D shape information can provide a whole new set of verification means, some of them being described and discussed in this work, specifically, visual enhancement tools and quantitative measurement of shape properties, for supporting, not replacing, the firearm examiner in reaching the final decision.     

Particle size analysis of sediments, soils and related particulate materials for forensic purposes using laser granulometry

Particle size is a fundamental property of any sediment, soil or dust deposit which can provide important clues to nature and provenance. For forensic work, the particle size distribution of sometimes very small samples requires precise determination using a rapid and reliable method with a high resolution. The Coulter trade mark LS230 laser granulometer offers rapid and accurate sizing of particles in the range 0.04-2000 microm for a variety of sample types, including soils, unconsolidated sediments, dusts, powders and other particulate materials. Reliable results are possible for sample weights of just 50 mg. Discrimination between samples is performed on the basis of the shape of the particle size curves and statistical measures of the size distributions. In routine forensic work laser granulometry data can rarely be used in isolation and should be considered in combination with results from other techniques to reach an overall conclusion.     

Analysis of 11 tetrameric STRs in wild boars for forensic purposes

STR profiling of animal species has a wide range of applications, including forensic identification, wildlife preservation, veterinary public health protection and food safety. We tested the efficacy of a multiplex PCR-based assay including 11 porcine-specific tetrameric STRs in a population sample of wild boars (n = 142) originating from Piedmont (North West Italy). Multiple deviations from Hardy–Weinberg expectations were observed, mostly due to a reduction in observed heterozygosity indicative of a high degree of inbreeding. A value of θ of 0.046 and an inbreeding coefficient of 0.089 were estimated. Combined power of discrimination and probability of exclusion values for the STR panel were 0.9999999999996 and 0.99989. In order to test the suitability of the method for meat traceability purposes, a domestic pig reference sample (n = 412), consisting of commercial lines commonly used in the meat production process, was also typed. A Bayesian cluster analysis carried out using the observed genotypes, showed a percentage of correct subspecies assignment of individual samples of 0.974 for wild boars and 0.991 for pigs, thus demonstrating the usefulness of the multiplex STR-typing system for discrimination purposes.     

Cloning for therapeutic purposes: ethical and policy considerations

This essay reviews how cloning techniques may be used for therapeutic purposes, analyzes ethical implications, and makes recommendations for public policy discourse. Although cloning may bring many potential benefits, they remain uncertain. Furthermore, human embryo research is morally problematic. Therefore, alternatives to human cloning for therapeutic aims should be sought at present. In addition to central ethical issues, public discourse should maintain an emphasis on the value of the human embryo over scientific expediency, the relativity of health, and the principle of justice. Society should support the laudable mission of medical research, while also attending to the moral concerns often threatened by the promises of scientific progress.     

The serological determination of myoglobin for forensic medical purposes

Possibility of using diagnosticum for myoglobin detection in passive hemagglutination reaction during evaluation of medicolegal objects is shown.     

Elemental analysis of soil samples for forensic purposes by inductively coupled plasma spectrometry — precision considerations

Major and trace elemental composition provides a powerful basis for forensic comparison of soils, sediments and rocks. However, it is important that the potential ‘errors’ associated with the procedures are fully understood and quantified, and that standard protocols are applied for sample preparation and analysis. This paper describes such a standard procedure and reports results both for instrumental measurement precision (repeatability) and overall ‘method’ precision (reproducibility). Results obtained both for certified reference materials and example soils show that the instrumental measurement precision (defined by the coefficient of variation, CV) for most elements is better than 2–3%. When different solutions were prepared from the same sample powder, and from different sub-sample powders prepared from the same parent sample, the CV increased to c. 5–6% for many elements. The largest variation was found in results for certified reference materials generated from 23 instrument runs over an 18 month period (mean CV = c. 11%). Some elements were more variable than others. W was found to be the most variable and the elements V, Cr, Co, Cu, Ni and Pb also showed higher than average variability. SiO₂, CaO, Al₂O₃ and Fe₂O₃, Rb, Sr, La, Ce, Nd and Sm generally showed lower than average variability, and therefore provided the most reliable basis for inter-sample comparison. It is recommended that, whenever possible, samples relating to the same investigation should be analysed in the same sample run, or at least sequential runs.