Trajectory reconstructions. I: Trace evidence in flight

This paper reviews the use of trace evidence recovered from spent bullets in helping to establish trajectories. The use of information derived from such trace evidence combined with that from geometrical techniques of trajectory reconstruction and other data is discussed. Five cases are reviewed in which the analysis of trace evidential materials adhering to bullets was used to help reconstruct the event.     

Forensic laboratory work in Burma (with special reference to the Office of the Chemical Examiner, Burma)

Burma is a country in Southeast Asia which is slightly smaller than Texas and has a population of 30 million people. The British colonial era brought the Chemical Examiner's laboratory to Burma. This was an all-purpose analytic laboratory. The forensic laboratory evolved within this structure as the need arose. The Medico-legal Division of this laboratory examined trace evidence, drugs, and body fluids of felons and there victims. Various aspects of investigation are discussed.     

Applications of Blue Light‐curing Acrylic Resin to Forensic Sample Preparation and Microtomy

This study discusses the results of an evaluation of a one‐part blue light‐curing acrylic resin for embedding trace evidence prior to the preparation of thin sections with a microtome. Through a comparison to several epoxy resins, the physical properties relevant to both trace evidence examination and analytical microscopy in general, including as viscosity, clarity, color, hardness, and cure speed, were explored. Finally, thin sections from paint samples embedded in this acrylic resin were evaluated to determine if, through smearing or impregnation, the resin contributed to the infrared spectra. The results of this study show that blue light‐curing acrylic resins provide the desired properties of an embedding medium, generate high‐quality thin sections, and can significantly simplify the preparation of paint chips, fibers and a multitude of other types of microscopic samples in the forensic trace evidence laboratory.     

Trace evidence: Here today,gone tomorrow?

The recent report of the National Research Council of the US National Academies “Strengthening Forensic Science in the United States: a Path Forward” found evidence that the level of scientific development and evaluation varies substantially among the forensic science disciplines. In this paper the status of trace evidence will be reviewed from an international perspective with particular reference to case studies. The paper will argue that the trace evidence discipline needs to learn from past experience and that serious coordinated action is required at an international level if trace evidence is to continue to meet the standards expected of forensic science in the future. The paper concludes that it is vital that trace evidence remains a key component of forensic investigation due to its important role in addressing the ‘what happened’ question.     

The nature of the deposit of substances in gunshot injuries from a smooth-bore hunting rifle]

Direct microscopic examinations of plain-barrel hunting gun-shot wounds may reveal on the victim's skin or clothes starch or paraffin particles or impressions thereof (a secondary shell trace). These data may evidence a specific charge of the cartridge and be used to specify the distance from which the shot was made, with an obligatory experimental shot made in each case.     

文件物证中痕迹信息的应用

能否准确地解读文件物证中的各种痕迹信息,有时对鉴定结论的做出至关重要。作者总结检案实践,参考有关文献,探讨了文件物证中痕迹信息的应用效果以及运用时需注意的问题。     

Placing the suspect at a PC: A preliminary study involving fingerprints on keyboards and mice

Digital devices now play an important role in the lives of many in society. Whilst they are used predominantly for legitimate purposes, instances of digital crime are witnessed, where determining their usage is important to any criminal investigation. Typically, when determining who has used a digital device, digital forensic analysis is utilised, however, biological trace evidence or fingerprints residing on its surfaces may also be of value. This work provides a preliminary study which examines the potential for fingerprint recovery from computer peripherals, namely keyboards and mice. Our implementation methodology is outlined, and results discussed which indicate that print recovery is possible. Findings are intended to support those operating at-scene in an evidence collection capacity.     

微痕量检验在致伤物推断与认定中的价值

致伤物可为侦查和审判提供准确、可靠的线索和证据。在法医学实践中，创内异物的分析与检测一直是致伤物推断和认定的重要途径之一。近年来，随着一系列先进检测技术的应用，使得致伤物在创周遗留的微痕量物证的发现和检验获得了重要进展。微痕量检验也由对火器伤射击残留物的分析扩展到钝器伤和锐器伤检验．并取得了初步的进展。     

数字图像技术辅助二次短路熔痕金相组织定量分析研究

以电气火灾二次短路熔痕显微组织为例，利用显微图像各组元的灰度特性，运用数字图像技术中的图像滤波、图像分割、轮廓提取方法对显微组织图像进行预处理，获取图像晶格和孔洞。结合体视学方法．对显微组织晶格粒径、孔洞大小等几何特征参数进行计算分析与测量，探讨数字图像技术辅助二次短路熔痕金相组织进行定量分析技术方法。     

The Evidentiary Significance of Automotive Paint from the Northeast: A Study of Red Paint

This population study was conducted to assess the frequency of physical, microscopical, and chemical properties of automotive paint chips. Population studies of trace evidence provide valuable analytical data for criminalists to assess evidentiary significance. Two‐hundred automotive paint chips were collected from auto body shops from the Northeastern United States. All samples were analyzed using stereomicroscopy, brightfield, and polarized light microscopy. Red paints were targeted for further analysis using a sequence of modern instrumental techniques commonly used by forensic paint examiners: Fourier‐transform infrared (FT‐IR), Raman, and ultraviolet–visible (UV–Vis) microspectroscopy. The discrimination potential of each analytical method was evaluated by inter‐comparing the paint samples. Results demonstrated that macroscopic and microscopic properties were able to differentiate 99.995% of the population (one undifferentiated pair out of 19,900). When combined with either FT‐IR or UV–Vis microspectroscopy, all paints were differentiated. The results of this research lead to the conclusion that one would not expect to encounter two indistinguishable paint chips originating from different sources during the investigation of a single event.     

论公共场所爆炸现场的快速处置与勘验

火车站等公共场所发生爆炸后,警方要采取应急警务对犯罪嫌疑人、受伤亡人员、现场秩序、痕迹物证保全与记录等开展快速处置与勘验。爆炸现场快速处置与勘验就是现场整体清理与转移,虽然现场的原始位置变化了,但是载体及其位置关系还在,特别是整体搬迁的残留物、抛出物等相互关系也要记录好。现场编号是勘查人员对现场的场所区域、痕迹物证分布、尸体位置等所做的标记,这种外在的符号添加和记录留存应该与现场客观记录的需要相匹配。     

论司法心理生理测试技术的价值定位

测谎作为一项新的刑事技术,在案件侦查中具有度量心理压力状态、提取犯罪心理痕迹、实施良性心理影响的独特功能。同时由于测谎结论的概率性、对谎言判断的间接性和适用范围的条件性等特点是测谎技术的局限性所在。根据我国目前现状,把测谎技术作为侦查工作的辅助性技术手段和审查判断证据的重要方法是恰当的价值定位,不排除在将来条件具备时成为直接提供诉讼证据的司法鉴定技术。     

The right to a fair trial as a conceptual framework for digital evidence rules in criminal investigations

Digital evidence and digital forensics have a significant impact on criminal investigation. This requires an examination if the fair trial principle remains sound in the new domain.In this paper the right to a fair trial in Art. 6 ECHR and its interpretation in case law is analysed in order to clarify its connection to evidence law and its specific application to the investigation stage of criminal proceedings. It is argued that the principle implicitly enshrines a framework for the development of universal evidence rules . Derived are two-groups of evidence rules: equality of arms based and presumption of innocence based. For each group specific challenges in the digital investigation are outlined and discussed in the context of a new governance model for digital evidence.     

犯罪心理画像论

犯罪心理画像是在研究罪案统计资料的基础上,运用心理学原理和技术,透视案件痕迹物证中的心理痕迹和心理现场,在重建犯罪过程中分析未知案犯的形象和行为、动机、心理过程、心理特征群等,从而确定作案人范围的侦查技术。考察犯罪心理画像研究的历史与现状。心理画像的实质是心理现场的重构,其逻辑线索是一种侦查推理,是关于作案人情况的假说。其归纳式心理画像和演绎式心理画像可结合起来,用其长处,避其短处。在借鉴现场分析、心理侦查、行为证据分析、地理画像等方法的基础上,我国应建立犯罪行为人性状和特征的数据库,完善相应的指标体系,以提高心理画像技术的科学性。     

Investigation into the usefulness of DNA profiling of earprints

DNA profiling of biological trace evidence has been used for many years. The application of this technique specifically to the DNA profiling of earprints has not to date been thoroughly investigated. This report presents the results of 60 earprints collected from three healthy adult volunteers under controlled laboratory conditions. DNA profile analysis revealed that high levels of non-donor alleles are observed when earprints are collected for DNA profiling. The source of these non-donor alleles is investigated and the impact that their presence within the profile may have on the use of this technique is discussed.     

技术侦查证据使用问题研究

随着技术侦查手段的广泛应用,技侦证据在司法实践中的具体使用问题受到了法学理论界和实务界越来越大的关注。为解决实践中的各种问题以及规范技侦证据在诉讼中的具体应用,2012年新《刑事诉讼法》明确规定了技侦证据的法律效力以及技侦证据使用的具体规则和法律程序。本文就该规定的相关修改背景、具体内涵进行了评析和论述,并就其未来具体实施可能出现的问题提出了相关的意见和建议。     

Commotio cordis: A case report of a fatal blow

Commotio cordis secondary to a blunt blow to the chest wall can result in ventricular fibrillation and sudden death in children. While it is commonly reported in adolescents during sporting activities, it may result from non-accidental trauma especially in infants and younger children. We report a case of a 6-month-old baby boy who presented to the emergency department in cardiac arrest. The patient's hospital records, postmortem imaging, and the autopsy results were reviewed. External examination of the infant did not reveal any evidence of trauma. Postmortem imaging revealed multiple healing posterior rib fractures and a metaphyseal corner fracture, both considered fractures highly specific for physical abuse. The autopsy revealed a structurally normal heart with no microscopic abnormalities. The infant's father confessed to hitting the child on the chest after which the child became unresponsive. Given the constellation of postmortem imaging and autopsy findings in addition to the father's confession, the child's death was ruled as a homicide secondary to commotio cordis. Since there are no structural and microscopic abnormalities in the heart autopsy in cases of commotio cordis, timely on-scene investigation and a thorough investigation regarding the mechanism of injury are required to make this diagnosis. Early identification of non-accidental trauma is crucial and can prevent further abuse in other siblings.     

Inter-comparison of unrelated fiber evidence

The foreign textile fibers recovered from one item of evidence from each of 20 unrelated crimes in three categories (bank robbery, kidnapping, and homicide) were cross-compared. The items of evidence were scraped to remove the trace evidence and a sample of the collected fibers was examined using a standard scheme of analysis. The fibers were examined with light microscopy (including polarized light microscopy), fluorescence microscopy, and microspectrophotometry. The fibers were divided into natural and manufactured groups and then categorized by color and generic (polymer) class. Cross-comparing all 2083 fibers resulted in 2,168,403 comparisons, after removing duplicate (same fiber) comparisons. Colorless and denim fibers were excluded from this study. No two fibers were found to exhibit the same microscopic characteristics and analytical properties. Therefore, it is rare to find two unrelated items that have foreign fibers that are analytically indistinguishable. These results corroborate other population studies conducted in Europe and target fiber studies conducted both in the US and in Europe.     

DNA evidence, probabilistic evaluation and collaborative tests

Forensic scientists working in 12 state or private laboratories participated in collaborative tests to improve the reliability of the presentation of DNA data at trial. These tests were motivated in response to the growing criticism of the power of DNA evidence. The experts' conclusions in the tests are presented and discussed in the context of the Bayesian approach to interpretation. The use of a Bayesian approach and subjective probabilities in trace evaluation permits, in an easy and intuitive manner, the integration into the decision procedure of any revision of the measure of uncertainty in the light of new information. Such an integration is especially useful with forensic evidence. Furthermore, we believe that this probabilistic model is a useful tool (a) to assist scientists in the assessment of the value of scientific evidence, (b) to help jurists in the interpretation of judicial facts and (c) to clarify the respective roles of scientists and of members of the court. Respondents to the survey were reluctant to apply this methodology in the assessment of DNA evidence.     

The spatial and temporal distribution of pollen in a room: Forensic implications

This paper presents two experimental studies that deal with the spatial and temporal distribution of pollen grains within a room of a domestic dwelling. The findings concur with the preliminary work of Morgan et al. [1] and provide greater detail as to the behaviour of pollen grains within indoor locations that are pertinent for forensic investigations. The spatial distribution of pollen in a room exhibits strong distance decay trends, with the majority of pollen recovered within 0.8 m of its source. The pollen was found to persist in increasing quantities during the time the flowers were in the room. This study also shows that 20 days after the flowers were removed, 25–32% of the original pollen was still present within the room. The influence of disturbance was investigated and whilst areas of high disturbance were found to retain less pollen than undisturbed locations, the influence of the proximity to source was a more dominant factor.These findings have significant implications for forensic investigation protocols, particularly the collection and interpretation phases of trace evidence analysis. The distribution of pollen around a room ensures that viable sources of trace pollen are available for transfer if contact is made between a location in the room and a suspect. The persistence of pollen many days after the flowers have been removed from a room indicates that many rooms in domestic dwellings will have distinctive assemblages that reflect the history of the flowers that have been displayed within that room in the past, and that these assemblages will persist and therefore be available for transfer. These preliminary findings indicate that investigation by forensic palynology in indoor domestic settings may well be an underutilised technique that has the potential to provide accurate and valuable intelligence and evidence for forensic enquiry.