Three-dimensional computer visualization of forensic pathology data

Despite a decade of use in US courtrooms, it is only recently that forensic computer animations have become an increasingly important form of communication in legal spheres within the United Kingdom. Aims Research at the University of Nottingham has been influential in the critical investigation of forensic computer graphics reconstruction methodologies and techniques and in raising the profile of this novel form of data visualization within the United Kingdom. The case study presented demonstrates research undertaken by Aims Research and the Department of Forensic Pathology at the University of Sheffield, which aims to apply, evaluate, and develop novel 3-dimensional computer graphics (CG) visualization and virtual reality (VR) techniques in the presentation and investigation of forensic information concerning the human body. The inclusion of such visualizations within other CG or VR environments may ultimately provide the potential for alternative exploratory directions, processes, and results within forensic pathology investigations.     

Forensic Terrestrial Photogrammetry from a Single Image

Abstract:  Forensic terrestrial photogrammetry is one of the most valuable and low-cost resources of spatial data available today. Due to the ephemeral crime scene characteristics, these photographs can often capture information that is never to be seen again. This paper presents a novelty approach for the documentation, analysis, and visualization of crime scenes for which only a single perspective image is available. The photogrammetric process consists of a few well-known steps in close-range photogrammetry: features extraction, vanishing points computation, camera self-calibration, 3D metric reconstruction, dimensional analysis, and interactive visualization. Likewise, the method incorporates a quality control of the different steps accomplished sequentially. As a result, several cases of study are presented in the experimental results section in order to test their viability. The full approach can be applied easily through the free software, sv3DVision, which has been evaluated by a number of police officers, forensic scientists, and forensic educators satisfactorily.     

A Three‐Locus,PCR‐based Method for Forensic Identification of Plant Material

Plant residue is currently an underutilized resource in forensic investigations despite the fact that many crime scenes, as well as suspects and victims, harbor plant‐derived residue that could be recovered and analyzed. Notwithstanding the considerable skill of forensic botanists, current methods of species determination could benefit from tools for DNA‐based species identification. However, DNA barcoding in plants has been hampered by sequence complications in the plant genome. Following a database search for usable barcodes, broad‐spectrum primers were designed and utilized to amplify and sequence the rbcL, trnL‐F, and rrn18 genetic loci from a variety of household plants. Once obtained, these DNA sequences were used to design species‐targeted primers that could successfully discriminate the source of plant residue from among the 21 species tested.     

The effects of deprivation on the time spent examining crime scenes and the recovery of DNA and fingerprints

DNA and fingerprint identifications are now accepted as an integral part of the investigation of a wide range of criminal offences from burglary and auto crime to serious and major crime. Despite this, there is still much variation between U.K. police forces in the recovery of fingerprint and DNA material from crime scenes. Analysis of burglary and auto crime data for Northamptonshire, U.K., during a 3-year period has enabled an examination of the relationship between the deprivation of the neighborhood in which the crime was committed and the level of service provided by Crime Scene Examiners. The results indicate that the time spent examining a crime scene for forensic evidence is not affected by the deprivation of the neighborhood. Further, there is no statistical significance between deprivation and the recovery of fingerprints from the crime scene. The relationship between deprivation and DNA recovery is, however, statistically significant with DNA being recovered more frequently from less deprived neighborhoods.     

The Use of an Alternate Light Source for Detecting Bones Underwater

When searching underwater crime scenes or disaster scenes for fragmentary human remains, it may be advantageous for forensic divers to be able to detect the presence of bones and teeth among other marine materials (such as shells and rocks). In terrestrial environments, this can typically be accomplished by visual and instrumental methods, but underwater conditions make it difficult to employ detection and sorting techniques in these environments. This study investigates fluorescence of bones and teeth and other marine materials using a submersible alternate light source (ALS) and concludes that an ALS can be a useful tool for detecting bones and teeth in underwater searches as well in terrestrial searches and laboratory environments. The results could impact the methods and equipment used by forensic divers and forensic anthropologists when searching for skeletal remains, potentially increasing the quantity and efficiency of forensic evidence recovered.     

Variation in the Measurement of Cranial Volume and Surface Area Using 3D Laser Scanning Technology

Abstract: Three‐dimensional (3D) laser scanner models of human crania can be used for forensic facial reconstruction, and for obtaining craniometric data useful for estimating age, sex, and population affinity of unidentified human remains. However, the use of computer‐generated measurements in a casework setting requires the measurement precision to be known. Here, we assess the repeatability and precision of cranial volume and surface area measurements using 3D laser scanner models created by different operators using different protocols for collecting and processing data. We report intraobserver measurement errors of 0.2% and interobserver errors of 2% of the total area and volume values, suggesting that observer‐related errors do not pose major obstacles for sharing, combining, or comparing such measurements. Nevertheless, as no standardized procedure exists for area or volume measurements from 3D models, it is imperative to report the scanning and postscanning protocols employed when such measurements are conducted in a forensic setting.     

The Relationship Between Deprivation and Forensic Opportunities with Stolen Vehicles

Abstract:  Collection and interpretation of forensic intelligence (primarily through DNA and fingerprint identifications) is an integral part of the investigation of criminal offenses ranging from burglary and vehicle crime to major crime. The forensic contribution depends not only on the successful recovery of material, but also the ability to identify potential offenders and apply this intelligence to solve the crime. This study examines burglary and vehicle crimes investigated by Northamptonshire Police (U.K.) by analyzing relationships between deprivation of a crime location and the recovery and identification of DNA and fingerprint material. The results show that, for stolen vehicles, although significantly more forensic material (both DNA and fingerprints) is recovered and identified in more deprived neighborhoods, this does not lead to a corresponding increase in solved cases. These findings are considered in relation to previous studies, which have advocated the prioritization of resources at crime scenes most likely to yield forensic material.     

Canine Population Data Generated from a Multiplex STR Kit for Use in Forensic Casework*

Abstract: Canine biological specimens are often part of the physical evidence from crime scenes. Until now, there have been no validated canine‐specific forensic reagent kits available. A multiplex genotyping system, comprising 18 short tandem repeats (STRs) and a sex‐linked zinc finger locus for gender determination, was developed for generating population genetic data assessing the weight of canine forensic DNA profiles. Allele frequencies were estimated for 236 pedigreed and 431 mixed breed dogs residing in the U.S. Average random match probability is 1 in 2 × 10³³ using the regional database and 1 in 4 × 10³⁹ using the breed dataset. Each pedigreed population was genetically distinct and could be differentiated from the mixed breed dog population but genetic variation was not significantly correlated with geographic transition. Results herein support the use of the allele frequency data with the canine STR multiplex for conveying the significance of identity testing for forensic casework, parentage testing, and breed assignments.     

100例卖淫女被杀案的法医学检验分析

目的 分析卖淫女被杀案件的规律特点,为此类案件检验侦查提供参考.方法 采用描述性研究方法,对2005至2010年的100例卖淫女被杀案件进行回顾性分析.结果 此类案件66.7%发生于21时至3时之间,88.0%发生于城市.4、7两月发案最多.85.0%的案件发生于室内.95.0%的死者年龄在16～40岁.38.1%的死...     

Developing a Spatial-Temporal Method for the Geographic Investigation of Shoeprint Evidence

Abstract:  This article examines the potential of a spatial-temporal method for analysis of forensic shoeprint data. The large volume of shoeprint evidence recovered at crime scenes results in varied success in matching a print to a known shoe type and subsequently linking sets of matched prints to suspected offenders. Unlike DNA and fingerprint data, a major challenge is to reduce the uncertainty in linking sets of matched shoeprints to a suspected serial offender. Shoeprint data for 2004 were imported from the Greater London Metropolitan Area Bigfoot database into a geographic information system, and a spatial-temporal algorithm developed for this project. The results show that by using distance and time constraints interactively, the number of candidate shoeprints that can implicate one or few suspects can be substantially reduced. It concludes that the use of space-time and other ancillary information within a geographic information system can be quite helpful for forensic investigation.     

Hierarchical,Three‐Dimensional Measurement System for Crime Scene Scanning

We present a new generation of three‐dimensional (3D) measuring systems, developed for the process of crime scene documentation. This measuring system facilitates the preparation of more insightful, complete, and objective documentation for crime scenes. Our system reflects the actual requirements for hierarchical documentation, and it consists of three independent 3D scanners: a laser scanner for overall measurements, a situational structured light scanner for more minute measurements, and a detailed structured light scanner for the most detailed parts of tscene. Each scanner has its own spatial resolution, of 2.0, 0.3, and 0.05 mm, respectively. The results of interviews we have conducted with technicians indicate that our developed 3D measuring system has significant potential to become a useful tool for forensic technicians. To ensure the maximum compatibility of our measuring system with the standards that regulate the documentation process, we have also performed a metrological validation and designated the maximum permissible length measurement error E_MPE for each structured light scanner. In this study, we present additional results regarding documentation processes conducted during crime scene inspections and a training session.     

Police Perceptions of Computer Crimes in Two Southeastern Cities: An Examination from the Viewpoint of Patrol Officers

Although scholars and law enforcement administrators have provided input on how local law enforcement is responding to various forms of computer crime and how officers perceive of it, patrol officers have been rarely surveyed to understand their perceptions of computer crime. Examining officer perceptions is vital considering that patrol officers are being asked to be more effective first responders to digital forensic crime scenes as a critical step in combating computer crimes at the local level. This study therefore addressed this gap by surveying patrol officers in two southeastern cities regarding their perceptions of computer crime, specifically regarding its uniqueness, offenders and targets, and seriousness and frequency in comparison to traditional forms of crime. Results indicated that many officers do not have strong opinions on several aspects of computer crime. However, they perceive it to be a serious problem and consider some computer crimes to be as serious as traditional forms of crime.     

Developing and Testing a Soil Property Database for Forensic Applications in Southern California

The research sought to develop and test a forensic database of surface soil variability within previously mapped geologic and soil units in southern California. This type of database could be used to link suspects to crime scenes or determine source locations of soil sample evidence. Variability was evaluated using (i) color, (ii) magnetic susceptibility, and (iii) particle‐size distribution. Soil properties were analyzed for their ability to discriminate source areas using stepwise discriminant analysis. The percent correct predictions for geologic unit groups ranged from 30% to 100%. A blind study experiment matched four of the 18 samples to their unit of origin with the first choice by stepwise discriminant analysis, and eight were matched as second and third choices. The probability of selecting the appropriate unit of origin increased by 54% over random chance and eliminated as much as 99% of the field area as a potential search location.     

The place of a forensic archaeologist at a crime scene involving a buried body

This paper examines the place that forensic archaeologists should hold at scenes of crime where a body has been buried. The forensic archaeologist is rapidly becoming a key player whose specialty should be explained, and role defined. A high level of interaction between the forensic archaeologist and other personnel implies good communications skills as well as a precarious mix of receiving orders, assistance and advice as well as giving directions to other staff. The extent to which each of these should be applied will be discussed as well as underlying the absolute need for forensic archaeologist to attend these types of scenes.     

The Spatial Distribution of Postblast RDX Residue: Forensic Implications

Locating exactly where trace explosive residue samples should be sought during sample collection at bomb scenes is not specified in the published literature or guidelines; in this area, it is generally acknowledged that forensic practices are based on tradition rather than evidence. This study investigated patterns in the spatial distribution of postblast 1,3,5‐trinitro‐1,3,5‐triazocyclohexane residue from a series of unconfined detonations, over a range of sampling sites, and at two different detonation heights. The amount of residue recovered from the sites decreased as a function of distance from the center of the explosion. [Correction added after online publication 27 December 2012: In the preceding sentence, “increased” was corrected to “decreased” to agree with the conclusion of the article.] As the height of the detonations increased, more residues were found from all sampling sites. The findings of this empirical study have a number of important practical implications including determining where residue samples are best sought at crime scenes.     

Human Factors Effecting Forensic Decision Making: Workplace Stress and Well‐being

Over the past decade, there has been a growing openness about the importance of human factors in forensic work. However, most of it focused on cognitive bias, and neglected issues of workplace wellness and stress. Forensic scientists work in a dynamic environment that includes common workplace pressures such as workload volume, tight deadlines, lack of advancement, number of working hours, low salary, technology distractions, and fluctuating priorities. However, in addition, forensic scientists also encounter a number of industry‐specific pressures, such as technique criticism, repeated exposure to crime scenes or horrific case details, access to funding, working in an adversarial legal system, and zero tolerance for “errors”. Thus, stress is an important human factor to mitigate for overall error management, productivity and decision quality (not to mention the well‐being of the examiners themselves). Techniques such as mindfulness can become powerful tools to enhance work and decision quality.     

Can computer forensic tools be trusted in digital investigations?

This paper investigates whether computer forensic tools (CFTs) can extract complete and credible digital evidence from digital crime scenes in the presence of file system anti-forensic (AF) attacks. The study uses a well-established six stage forensic tool testing methodology based on black-box testing principles to carry out experiments that evaluate four leading CFTs for their potential to combat eleven different file system AF attacks. Results suggest that only a few AF attacks are identified by all the evaluated CFTs, while as most of the attacks considered by the study go unnoticed. These AF attacks exploit basic file system features, can be executed using simple tools, and even attack CFTs to accomplish their task. These results imply that evidences collected by CFTs in digital investigations are not complete and credible in the presence of AF attacks. The study suggests that practitioners and academicians should not absolutely rely on CFTs for evidence extraction from a digital crime scene, highlights the implications of doing so, and makes many recommendations in this regard. The study also points towards immediate and aggressive research efforts that are required in the area of computer forensics to address the pitfalls of CFTs.     

The use of simulated crime scenes in teaching undergraduate forensic sciences: Implementing an active learning approach to forensics

Incorporating a simulated crime scene into one’s pedagogy in forensic science undergraduate courses allows students the opportunity to experience a realistic scenario while demonstrating their knowledge and enhancing their critical thinking skills. The purpose of this paper is to examine an active learning approach to using simulated crime scenes to provide an impactful learning experience for students. While potentially challenging for the instructor, constructing a crime scene scenario can provide students with hands-on practical experience while helping to dispel forensic science misconceptions. Through many years of creating crime scenes, best practices for using such high impact activities in forensic science courses are described in detail, including preparatory exercises that culminate in the final crime scene scenario, considerations in preparing and constructing a crime scene activity, and supervising and assessing students once the activity begins. Three major challenges to implementing active learning exercises such as simulated crime scenes in undergraduate forensic science programs include high workload for instructors, limited supplies, and lack of suitable facilities. Workload solutions include instructors and departments considering the cost and benefit of course releases to improve curriculum and student enrollment. Supplies and facilities solutions involve innovation in reuse and repurposing of supplies, and instructor flexibility in using classroom and outdoor spaces.     

开发高灵敏度血痕发光试剂用于法医现场检测

目的开发高灵敏度血痕发光试剂用于法医现场检测。方法本项目通过借鉴ECL发光的原理,通过化学电子链的乒乓共轭激活原理,使用均匀设计实验方法优化条件,合成多个新化合物,开发出新型高灵敏度血痕发光试剂。结果本项目开发的高灵敏度血痕发光试剂灵敏度高,发光时间长,在血液稀释1000倍的情况下,使用Chemi Scope3300化学发光成像系统读取荧光值,经过灰度转化最高值达到56,发光时间达到10分钟。结论本项目成功开发了高灵敏度血痕发光试剂,可以应用于法医现场检测。