Soil forensics: How far can soil clay analysis distinguish between soil vestiges?

Soil traces are useful as forensic evidences because they frequently adhere to individuals and objects associated with crimes and can place or discard a suspect at/from a crime scene. Soil is a mixture of organic and inorganic components and among them soil clay contains signatures that make it reliable as forensic evidence. In this study, we hypothesized that soils can be forensically distinguished through the analysis of their clay fraction alone, and that samples of the same soil type can be consistently distinguished according to the distance they were collected from each other. To test these hypotheses 16 Oxisol samples were collected at distances of between 2 m and 1.000 m, and 16 Inceptisol samples were collected at distances of between 2 m and 300 m from each other. Clay fractions were extracted from soil samples and analyzed for hyperspectral color reflectance (HSI), X-ray diffraction crystallographic (XRD), and for contents of iron oxides, kaolinite and gibbsite. The dataset was submitted to multivariate analysis and results were from 65% to 100% effective to distinguish between samples from the two soil types. Both soil types could be consistently distinguished for forensic purposes according to the distance that samples were collected from each other: 1000 m for Oxisol and 10 m for Inceptisol. Clay color and XRD analysis were the most effective techniques to distinguish clay samples, and Inceptisol samples were more easily distinguished than Oxisol samples. Soil forensics seems a promising field for soil scientists as soil clay can be useful as forensic evidence by using routine analytical techniques from soil science.     

The forensic examination of structural fires in Victoria,Australia: Decision-making processes and impact on judicial outcomes

There is a body of published research that has evaluated the contribution of forensic science to the criminal justice system, but many disciplines of forensic science remain unexplored in this regard. The aim of this study was to examine the contribution that forensic fire examination services provide to criminal investigations and court processes in arson cases. Forensic fire examination services differ in a number of ways to the disciplines covered in previous research on the impact of forensic evidence on justice outcomes. Forensic fire examinations involve a combination of scene examination and laboratory analyses, and the results can provide critical evidence of whether an incident that has occurred is a criminal offence (i.e. whether a fire has occurred as the result of an act of arson). Forensic fire examination is also a discipline that has faced challenges and undergone development in recent decades regarding its scientific basis and the issue of contextual bias. In this study, data were collated for 273 structural fires that were examined by the forensic fire services in Victoria, Australia. In this jurisdiction, scene and laboratory forensic services are delivered within short time frames with a focus on providing impartial scientific and investigative services to assist criminal investigations conducted by police. The current dataset was highly skewed in terms of criminal justice outcomes and was not suitable for conducting the planned statistical analyses. Nonetheless, the pattern of findings obtained suggested that the inclusion of forensic evidence which supported the prosecution of arson may be associated with an increased likelihood of suspects being charged and defendants found guilty. Examination of the decision-making process of the forensic fire examiners has provided insight into the variety of evidence that is considered by forensic experts in reaching the important conclusion about the origin and cause of structural fires.     

植物物证的法医学应用

随着植物物证在案件侦破过程中的作用日益明显,应用植物学研究方法为刑事案件提供线索、证据的“法医植物学”越来越受到关注。法医植物学常用的实验技术有形态学检验、理化检验、分子遗传学检验等。本文通过整理法医植物学研究的相关文献及案例,以列举的形式简要阐述不同检验方法的利弊,总结法医植物学应用中需要注意的问题,供案件现场勘验时参考。     

An Overview of 3D Printing in Forensic Science: The Tangible Third-Dimension

There has been a rapid development and utilization of three-dimensional (3D) printing technologies in engineering, health care, and dentistry. Like many technologies in overlapping disciplines, these techniques have proved to be useful and hence incorporated into the forensic sciences. Therefore, this paper describes how the potential of using 3D printing is being recognized within the various sub-disciplines of forensic science and suggests areas for future applications. For instance, the application can create a permanent record of an object or scene that can be used as demonstrative evidence, preserving the integrity of the actual object or scene. Likewise, 3D printing can help with the visualization of evidential spatial relationships within a scene and increase the understanding of complex terminology within a courtroom. However, while the application of 3D printing to forensic science is beneficial, currently there is limited research demonstrated in the literature and a lack of reporting skewing the visibility of the applications. Therefore, this article highlights the need to create good practice for 3D printing across the forensic science process, the need to develop accurate and admissible 3D printed models while exploring the techniques, accuracy and bias within the courtroom, and calls for the alignment of future research and agendas perhaps in the form of a specialist working group.     

Nature and place of crime scene management within forensic sciences

This short paper presents the preliminary results of a recent study aimed at appreciating the relevant parameters required to qualify forensic science as a science through an epistemological analysis. The reader is invited to reflect upon references within a historical and logical framework which assert that forensic science is based upon two fundamental principles (those of Locard and Kirk). The basis of the assertion that forensic science is indeed a science should be appreciated not only on one epistemological criteria (as Popper's falsification raised by the Daubert hearing was), but also on the logical frameworks used by the individuals involved (investigator, expert witness and trier of fact) from the crime scene examination to the final interpretation of the evidence. Hence, it can be argued that the management of the crime scene should be integrated into the scientific way of thinking rather than remain as a technical discipline as recently suggested by Harrison.     

物证鉴定中的物证污染问题

物证污染是影响物证鉴定结果的最重要因素之一,它会损害物证鉴定结论质量甚至造成错误的鉴定结论。随着以法医DNA检验为代表的物证鉴定技术检验灵敏度的提高,物证污染出现的可能性及其造成的危害程度都显著增加。物证污染有多种形式和来源,可能发生在犯罪现场或实验室。采取适当的污染防范措施可以有效降低物证污染发生的可能性,及时监测和发现物证污染可以将污染造成的危害降到最低。     

Forensic science does not start in the lab: the concept of diagnostic field tests

An attempt to improve an analytical system can focus either on the actual processing or on the input. In forensic science, much emphasis has been placed on improving laboratory procedures, as though the input is already the best that can be obtained. Means of improving the basic input have gained much less attention. Yet, it must be agreed that even the best laboratory cannot gain from an item more than has been contained in it when it arrived from the field. The detection of latent materials at the crime scene by physical or chemical techniques and the diagnostic examination of material already discovered belong to the concept of diagnostic field tests. This group also includes "mapping" for the presence of certain materials, such as latent fingerprints through the distribution of amino acids on the surface. These tests are conducted outside the laboratory, without sophisticated instrumentation, at the crime scene, the suspect's home, or elsewhere. A significant advantage of the use of diagnostic field tests is the ability to deal with "dissipating evidence" such as gunshot residue or explosive traces on the hands of suspects. If time is lost, there is a risk of losing such evidence, which is liable to deteriorate rapidly. In my presentation, I will discuss older and some newly developed forensic field tests, with specific emphasis on the Israeli experience.     

Considerations on the ASTM Standards 1789‐04 and 1422‐05 on the Forensic Examination of Ink

Abstract: The ASTM standards on Writing Ink Identification (ASTM 1789‐04) and on Writing Ink Comparison (ASTM 1422‐05) are the most up‐to‐date guidelines that have been published on the forensic analysis of ink. The aim of these documents is to cover most aspects of the forensic analysis of ink evidence, from the analysis of ink samples, the comparison of the analytical profile of these samples (with the aim to differentiate them or not), through to the interpretation of the result of the examination of these samples in a forensic context. Significant evolutions in the technology available to forensic scientists, in the quality assurance requirements brought onto them, and in the understanding of frameworks to interpret forensic evidence have been made in recent years. This article reviews the two standards in the light of these evolutions and proposes some practical improvements in terms of the standardization of the analyses, the comparison of ink samples, and the interpretation of ink examination. Some of these suggestions have already been included in a DHS funded project aimed at creating a digital ink library for the United States Secret Service.     

Public beliefs about the accuracy and importance of forensic evidence in the United States

Recent advances in forensic science, especially the use of DNA technology, have revealed that faulty forensic analyses may have contributed to miscarriages of justice. In this study we build on recent research on the general public’s perceptions of the accuracy of 10 forensic science techniques and of each stage in the investigation process. We find that individuals in the United States hold a pessimistic view of the forensic science investigation process, believing that an error can occur about half of the time at each stage of the process. We find that respondents believe that forensics are far from perfect, with accuracy rates ranging from a low of 55% for voice analysis to a high of 83% for DNA analysis, with most techniques being considered between 65% and 75% accurate. Nevertheless, respondents still believe that forensic evidence is a key part of a criminal case, with nearly 30% of respondents believing that the absence of forensic evidence is sufficient for a prosecutor to drop the case and nearly 40% believing that the presence of forensic evidence – even if other forms of evidence suggest that the defendant is not guilty – is enough to convict the defendant.     

Unlocking the potential of forensic traces: Analytical approaches to generate investigative leads

Forensic investigation involves gathering the information necessary to understand the criminal events as well as linking objects or individuals to an item, location or other individual(s) for investigative purposes. For years techniques such as presumptive chemical tests, DNA profiling or fingermark analysis have been of great value to this process. However, these techniques have their limitations, whether it is a lack of confidence in the results obtained due to cross-reactivity, subjectivity and low sensitivity; or because they are dependent on holding reference samples in a pre-existing database. There is currently a need to devise new ways to gather as much information as possible from a single trace, particularly from biological traces commonly encountered in forensic casework. This review outlines the most recent advancements in the forensic analysis of biological fluids, fingermarks and hair. Special emphasis is placed on analytical methods that can expand the information obtained from the trace beyond what is achieved in the usual practices. Special attention is paid to those methods that accurately determine the nature of the sample, as well as how long it has been at the crime scene, along with individualising information regarding the donor source of the trace.     

Photographic Image Comparison of Vegetation

Images and videos are common types of evidence in crime scene investigations and laboratory analysis. Images may be taken by the suspect and/or by crime scene investigators and may serve as crucial elements in forensic laboratory analysis. Forensic photographic image comparison is the process of comparing one or more objects or persons in photographs/images when at least one image is known to be related to a crime. The forensic examiner usually compares the images in order to determine whether or not an association between the exhibits in the images can be made. This paper proposes an extension to the currently prevalent photographic image examination method. The extension introduces comparison of landscape and vegetation over time. It is revealed that similarities between images may still be found between the period of time the suspect photograph was taken and the period the crime scene investigator took the photograph from the same area. In this case report, two suspects to be involved in growing a marijuana field were arrested by the police. The forensic experts were asked to examine images taken by the crime scene investigators and to compare them to the images found in the suspects’ phones. They then tried to determine whether the suspects could be linked to the specific locations. While applying techniques derived from morphological comparison methodologies, the plants at the scene provided significant additional information. A tree trunk, branches, and twigs on a hedge in the photographs revealed specific individual characteristics that led the examiner to reach a conclusive decision.     

From crime scene to courtroom: A review of the current bioanalytical evidence workflows used in rape and sexual assault investigations in the United Kingdom

Sexual assault casework requires the collaboration of multiple agency staff to formalise an investigative pipeline running from crime scene to court. While the same could be said of many other forensic investigations, few require the additional support of health care staff and the combined forensic involvement of body-fluid examiners, DNA experts and analytical chemists. The sheer amount of collaborative effort between agencies is laid out through a detailed examination of the investigative workflow from crime scene to courtroom with each step in the pipelines detailed and discussed. Beginning with a review of sexual assault legislation in the United Kingdom this article details how sexual assault investigations are initiated by police and supported by sexual assault referral centre (SARC) staff who are often the first responders providing primary healthcare and patient support to victims while simultaneously collecting and assessing forensic evidence. Detailing the myriad of evidential material that can be documented and collected at the SARC, the review identifies and categorises key forensic tests to first detect and identify body-fluids recovered from evidence through to the secondary analysis of DNA to help identify the suspect. This review also focusses on the collection and analysis of biological material used to support the allegation that the sexual activity was non-consensual and provides a breakdown of common marks and trauma as well as a review of common analytical methods used to infer Drug Facilitated Sexual Assault (DFSA). The culmination of the investigative pipeline is discussed by reviewing the Rape and Serious Sexual Assault (RASSO) workflow used by the Crown Prosecution Service before providing our thoughts on the future of forensic analysis and possible changes to the described workflows.     

Human Leukocyte Antigen alleles as an aid to STR in complex forensic DNA samples

Human biological samples with multiple contributors remain one of the most challenging aspects of DNA typing within a forensic science context. With the increasing sensitivity of commercially available kits allowing detection of low template DNA, complex mixtures are now a standard component of forensic DNA evidence. Over the years, various methods and techniques have been developed to try to resolve the issue of mixed profiles. However, forensic DNA analysis has relied on the same markers to generate DNA profiles for the past 30 years causing considerable challenges in the deconvolution of complex mixed samples. The future of resolving complicated DNA mixtures may rely on utilising markers that have been previously applied to gene typing of non-forensic relevance. With Massively Parallel Sequencing (MPS), techniques becoming more popular and accessible even epigenetic markers have become a source of interest for forensic scientists.The aim of this review is to consider the potential of alleles from the Human Leukocyte Antigen (HLA) complex as effective forensic markers. While Massively Parallel Sequencing of HLA is routinely used in clinical laboratories in fields such as transplantation, pharmacology or population studies, there have not been any studies testing its suitability for forensic casework samples.     

电子物证检验

目的阐述电子物证检验技术的专业内容和组成,以及开展电子物证检验的作用和重要意义;方法研究美国、欧洲和国内电子证据及其检验鉴定的数据资料,结合国内物证检验技术发展现状和需求,论证电子物证检验技术;结果提出了电子物证检验定义、检验对象、技术方法、特点作用以及尽快在国内建立电子物证检验专业等观点;结论电子物证检验是关于识别、发现、提取、保存、恢复、展示、分析和鉴定电子设备中存在的电子信息(电子证据)的科学技术,其检验结果可以作案件侦查线索或法庭证据。开展电子物证检验可以有效提高犯罪侦查效率。     

Turf wars: authority and responsibility for the investigation of mass graves

Mass graves are complex products of large-scale crimes. Such scenes pose four conceptual challenges to investigators and forensic experts: the individual victim, the crime, the setting, and the statistical. Exhumation and post-mortem examination of mortal remains with associated personal and forensic evidence require integrated management of core forensic personnel including investigators, archaeologists, anthropologists, odontologists and pathologists, among whom there is overlapping expertise. The key to avoiding competition and ill-will among experts is to recognize that all such experts should be enabled to make known how their expertise matches with the temporal and spatial boundaries of victim, crime and setting. In turn, they should be apprised of where they fit into the overall judicial process and their limits within the investigation. Consequently, each expert requires access to the factual background of the case, to the site and its contents throughout the investigation. Each forensic team member has a responsibility to influence the investigation--throughout its course when possible--to make findings within their areas of expertise, and to make these available to the rest of the team so as to contribute most meaningfully to the aims of the investigation, both forensic and humanitarian. The on-site crime scene manager has an overarching role to enable integrated access to the complete scene and its contents by each forensic expert team member. In other words, the forensic scientist is given access and the ability to influence the investigation while control of evidence from the site as to identity and criminal activity are maintained by the crime scene manager. This contribution is directed at both the crime scene manager and each forensic expert; it describes the essential spatial and temporal parameters of an expert's opinion so as to encourage cooperation, and discourage conflict, within the forensic team.     

Traceology,criminalistics, and forensic science

There is a serious issue within the forensic science community, which even extends outside of the field. The role of the scientist in the investigation of crime has been increasingly confined to the laboratory, which has been accompanied by the conflation of the terms forensic science and criminalistics. This unfortunate situation has been festering for years. To make matters worse, the era of the proactive, problem-defining, criminalist (generalist) is waning, and possibly over. Present-day “criminalists” are treated as little more than reactive, protocol-constrained, laboratory technicians, with few, if any, consequential crime scene roles. In most cases, these “criminalists” merely respond to routine requests from prosecutors and police. The absence of science at the front end of forensic investigations, i.e., the scene, has resulted in biased, ineffective, inefficient, and/or erroneous outcomes with immediate and long-term societal impacts. To disentangle this imbroglio, we propose the use of another term, traceology, which has seen limited use worldwide except in the field of archaeology. With respect to criminalistics, this term has been previously proposed by Margot (20–21). Traceology is an historical science, dealing with the examination, analysis, and scientific interpretation of event traces (signs or remnants) of earlier activities. In this commentary, we define and redefine familiar, but ambiguous, terms and concepts with the hope of recapturing the essence of criminalistics (32), which we suggest is best termed traceology.     

Multi-technique comparison of source and primary transfer soil samples: an experimental investigation.

The comparison of soil samples is of long-standing and increasing interest in forensic science. Routine comparisons should involve the use of several techniques in combination. A wide range of analytical techniques can be used, choice being dependent on several factors including sample size and character, time constraints and cost limitations. In this paper results are presented for experiments carried out to test the effectiveness of four of the available analytical techniques (spectro-photometric colour determination, laser diffraction particle size analysis, stable isotope analysis and chemical element analysis) used to compare single source and primary transfer soil samples. Four soil types and five footwear types were used. All four techniques showed excellent precision and good resolving power between soil types. Only relatively small differences were obtained between source and transferred soil samples in terms of colour, stable carbon and nitrogen isotope ratios and elemental chemistry. Slight but significant differences were found in grain size, indicating that the primary transfer process is to some extent grain size selective.     

Forensic Significance of Gunshot Impact Marks on Inanimate Objects: The Need for Translational Research

Wherever an impact mark is found, either on the surface or on the recovered projectile, it is important for forensic investigators to extract useful information in solving shooting-related cases. This article reviews a collection of works on examination of impact marks upon striking of projectiles on inanimate objects, emphasizing on the retrievable information from a shooting scene and their forensic significance in shooting event reconstruction. Literature suggested that impact marks on target surfaces and the degree of deformation on striking projectiles vary according to different combinations of ammunition and surface materials. It was noted that conditions in real-case scenarios further differed unpredictably in comparison with controlled studies, where forensic investigation should be treated as case-specific basis. Furthermore, the way forensic science is researched and applied operationally has to be reconsidered to reduce the gap via translational approach for more effective use of forensic evidence.     

The contribution of forensic science to crime analysis and investigation: forensic intelligence

The debate in forensic science concentrates on issues such as standardisation, accreditation and de-contextualisation, in a legal and economical context, in order to ensure the scientific objectivity and efficiency that must guide the process of collecting, analysing, interpreting and reporting forensic evidence. At the same time, it is recognised that forensic case data is still poorly integrated into the investigation and the crime analysis process, despite evidence of its great potential in various situations and studies. A change of attitude is needed in order to accept an extended role for forensic science that goes beyond the production of evidence for the court. To stimulate and guide this development, a long-term intensive modelling activity of the investigative and crime analysis process that crosses the boundaries of different disciplines has been initiated. A framework that fully integrates forensic case data shows through examples the capital accumulated that may be put to use systematically.     

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。