Context Effects in Forensic Entomology and Use of Sequential Unmasking in Casework

Context effects are pervasive in forensic science, and are being recognized by a growing number of disciplines as a threat to objectivity. Cognitive processes can be affected by extraneous context information, and many proactive scientists are therefore introducing context‐minimizing systems into their laboratories. Forensic entomologists are also subject to context effects, both in the processes they undertake (e.g., evidence collection) and decisions they make (e.g., whether an invertebrate taxon is found in a certain geographic area). We stratify the risk of bias into low, medium, and high for the decisions and processes undertaken by forensic entomologists, and propose that knowledge of the time the deceased was last seen alive is the most potentially biasing piece of information for forensic entomologists. Sequential unmasking is identified as the best system for minimizing context information, illustrated with the results of a casework trial (n = 19) using this approach in Victoria, Australia.     

Estimating Crime Laboratory Efficiency in the Testing of Sexual Assault Kits,

Over the past decade, the large numbers of untested sexual assault kits (SAKs) have been highlighted as a systematic problem that jeopardizes or delays justice for victims. Considering the benefits of testing SAKs, researchers have worked to shed light on why sexual assault evidence has not been effectively submitted to and processed by crime laboratories. Missing from this discourse has been an understanding of the types of practices or qualities that encourage efficiency in the testing of SAKs in crime laboratories. We analyzed results of a national survey administered to all publicly funded state and local crime laboratories (N = 132 respondents) to provide critical information about (i) the extent to which laboratories are testing all of the SAKs possible given the resources they have available; and (ii) the impact that staffing, equipment, policies, and other practices have on SAK testing efficiency. We find that the average laboratory tests only about 69% of the SAKs possible given the resources available to them. However, although technical inefficiencies explain a large proportion of the number of untested SAKs, the accumulation of untested SAKs must also be attributed to laboratories having insufficient resources (e.g., too few forensic analysts). Moreover, results from stochastic frontier models show that doubling the number of forensic analysts in the typical laboratory would allow them to expand their SAK testing capacity by nearly 50%. Implications of these findings are discussed as they relate to the prioritization of resources for crime laboratories, which often operate under strict budgetary realities.     

Forensic genetic value of 27 Y-STR loci (Y-Filer® Plus) in the South African population

South Africa has one of the highest rape statistics in the world, with an average of 117 rapes reported daily. Y-STR genotyping is becoming a popular tool in the analysis of DNA evidence collected after a crime of a sexual nature has been committed, but has yet to be implemented in South Africa’s forensic laboratories. This study aimed to investigate the forensic value of the 27 Yfiler™ Plus loci in the South African population. A total of 271 samples from the African, Asian/Indian, Mixed Ancestry¹, and Caucasian populations at the University of the Free State in Bloemfontein, South Africa were amplified and analysed using ThermoFisher Scientific’s Yfiler™ Plus PCR Amplification kit. Of the 271 samples, 261 were identified to be unique, with an overall discrimination capacity of 98.15%. Discrimination capacities ranged from 91.67% for the Asian/Indian population to 100% for the Mixed Ancestry population. The haplotype diversity across the four populations is 0.9999, with an average gene diversity across all loci of 0.717. The forensic parameters estimated in this study provide evidence for the potential use of the commercial Yfiler™ Plus PCR amplification kit in a forensic application in South Africa.     

The origin of evidence

Forensic science is an applied science based on the laws of physics and chemistry. Over time, a set of fundamental concepts has developed that apply specifically to a forensic analysis. Traditionally, five concepts have been articulated: transfer, identification, individualization, association between source and target, and reconstruction. We suggest that an additional sixth concept, the idea that matter must divide before it can be transferred, is necessary to complete the paradigm. Divisible matter is particularly useful in describing physical match evidence. Additionally, we propose a paradigm that logically divides into scientific principles that govern the generation of evidence, and processes that pertain to the recognition, analysis, and interpretation of evidence. The principles of divisible matter and transfer pertain to the generation of evidence before and during the crime event; the processes of identification, classification or individualization, association, and reconstruction describe the practice of forensic science starting with the recognition of an item as evidence.     

An exercise in scientific problem-solving: Illustrating the utility of the principles of the Sydney Declaration

In forensic science, scientific problem-solving is characterized by the recognition of traces as part of iterative reasoning processes to assign meaning to those traces in order to interpret and reconstruct events. Through a set of fundamental principles, the Sydney Declaration presents a foundation of forensic science through the lens of a scientist. The distinction between a scientist and a technician may require clarification—where a prototypical technician follows a prescribed set of ‘standard operating procedures’ and may be limited in the interpretation of the resultant data, the scientist utilizes knowledge, skills, experience and imagination to identify the issue at hand and develop lines of inquiry for testing and interpretation. This case report draws on the Sydney Declaration in order to highlight the importance of learning about events from careful consideration of both obvious and less obvious traces. A case involving the assault of a police officer is examined to illustrate the use of the Principles: the problem originally defined by investigators at the scene and later by prosecutors resulted in incorrect analysis and interpretation of traces, hampering efforts at an accurate reconstruction of events. This exercise serves to demonstrate that in order to engage in scientific problem-solving, it is necessary to apply observation and reasoning in forensic investigations in order to yield an outcome that can be clearly articulated. The overarching goal is to support the drive to improve forensic science practice, education, and research through a case illustrating the value of the principles of the Sydney Declaration.     

物证鉴定的能力验证

能力验证是物证鉴定质量保障体系的重要组成部分,可以非常有效的评估、监控和提高实验室物证鉴定能力和质量。本文论述了物证鉴定能力验证的主要方法、形式、类型和特点,以及在物证鉴定实验室质量管理中的具体应用,介绍了国外物证鉴定实验室参加能力验证活动的历史和现状,并提出在我国物证鉴定实验室广泛开展能力验证活动的思考。     

Perceptions of blind proficiency testing among latent print examiners

In recent years, scholars have levied multiple criticisms against traditional proficiency testing procedures in forensic laboratories. Consequently, on several occasions, authorities have formally recommended that laboratories implement blind proficiency testing procedures. Implementation has been slow, but laboratory management has increasingly expressed interest in initiating blind testing in at least some forensic disciplines, with some laboratories conducting blind testing in almost all disciplines. However, little is known about how a key population perceives blind proficiency testing, i.e., forensic examiners. We surveyed active latent print examiners (N = 338) to explore perceptions of blind proficiency testing and determine whether beliefs varied between examiners who work for laboratories with and without blind proficiency testing. Results suggest that examiners do not hold particularly strong beliefs about such procedures, but that examiners who work in laboratories with blind proficiency testing procedures view them significantly more positively than those who do not. Further, examiner responses provide insight into potential obstacles to continued implementation.     

Shifting forensic science focus from means to purpose: A path forward for the discipline?

Forensic science is facing a persistent crisis that is often addressed by organizational responses, with a strong focus on the improvement and standardisation of means and processes. However, organisations and processes are highly dependent on the political, economical and legal structures in which they operate. This may explain why most proposed solutions had difficulties in addressing the crisis up to now, as they could hardly be applied transversally to all forensic science models. Moreover, new tools and technologies are continuously developed by a quasi-infinite number of different scientific disciplines, thus leading to further diversity and fragmentation of forensic science. In this paper, it is proposed to shift the focus from means to purpose and consider forensic science current challenges in terms of discipline, before addressing organisations’ specific issues. As a distinct discipline, forensic science can refocus research and development on shared principles and purposes, such as reconstructing, monitoring, and preventing crime and security issues. This focus change will facilitate a better understanding of the trace as the object of study of forensic science and eventually lead to a more impactful and long-lasting effect. This approach will also foster the development of a forensic science culture (instead of a primarily technological culture) unified by purpose rather than means through more relevant education and research.     

Stereochemical Analysis of Methorphan Using (−)‐Menthyl Chloroformate

Abstract: Forensic laboratories around the world have seen an increase in the number of drug seizures containing methorphan. Levomethorphan is a narcotic and a controlled substance, and its enantiomer dextromethorphan is an antitussive agent used in over‐the‐counter medications. For the forensic analysis of seized drugs containing methorphan, it is important to report the stereochemical composition of the drug. Ideally, a method based on common forensic laboratory instrumentation is desirable. The use of the chiral derivatizing agent (?)‐menthyl chloroformate followed by routine gas chromatography–mass spectrometry analysis of the derivative was shown to successfully determine the stereochemical composition of methorphan. This approach was applied to a street seizure containing methorphan proving that it was pure dextromethorphan. The derivatives of dextro‐ and levomethorphan were subjected to mass spectroscopic and nuclear magnetic resonance analysis, which confirmed that the structure of the derivatives remained unchanged as a result of the derivatization process.     

The introduction of forensic advisors in Belgium and their role in the criminal justice system

Forensic advisors (FA) at the National Institute for Criminalistics and Criminology (NICC), generalists in forensic science, act as an advising body to the magistrate to improve communication between the various parties involved in the investigation: magistrate, police and crime scene investigators, and forensic experts. Their role is manifold, but their main objectives are to optimise trace processing by selecting the most pertinent traces in the context of the case and by advising magistrates on the feasibility of forensic analyses in particular circumstances in regards to the latest technical advances.Despite the absence of a legal framework governing their role and involvement in judicial cases, the demand for their services has increased over the years. Initially, forensic advisors were called for complex homicide cases. Due to the proximity with the Public Prosecutor's Office, the types of offences for which their expertise was sought have become more diverse (mainly including robbery, burglary and sexual assault cases), leading to a diversity in the types of cases handled by the forensic advisors (complex, simple and review).In many of the cases they are requested for, in addition to consulting on the best analytical strategy, forensic advisors also assume the role of case coordinator regarding the seized objects and their respective analyses. Indeed, in the majority of cases treated by the FAs, two or more types of expertise have been requested and performed, either at the internal laboratories of NICC or at external laboratories.This paper explains the role of the forensic advisors in Belgium, the path that let to their current status and problems encountered.     

Report of the blind trial of the Cetus Amplitype HLA DQ alpha forensic deoxyribonucleic acid (DNA) amplification and typing kit

The AmpliType HLA DQ alpha forensic DNA amplification and typing kit is designed for the qualitative analysis of the human leukocyte antigen (HLA) DQ alpha alleles present in deoxyribonucleic acid (DNA) extracted from forensic samples. The AmpliType kit is the first forensic DNA typing product based on the GeneAmp polymerase chain reaction (PCR) process. The kit was evaluated by five forensic science laboratories (test sites) to assess their ability to perform DNA typing using PCR on sample types typically encountered by forensic laboratories. None of the DNA-containing samples was mistyped. Of the 180 DNA-containing samples analyzed, results were reported for 178 (98.9%). Of the 178 samples with results, all were correctly typed. Two sites did not report a result for one sample each. Four of the five laboratories experienced no significant levels of contamination in the DNA-containing samples. At the one site with the highest number of DNA-containing samples with contamination, the typing results were not compromised. This site was able to correct the contamination problem through simple procedural changes and stricter attention to sterile technique. Blank controls were important to monitor contamination. In conclusion, the trial demonstrated that forensic science laboratories are capable of setting up a PCR-based DNA typing laboratory and successfully using the AmpliType HLA DQ alpha forensic DNA amplification and typing kit to analyze forensic samples.     

Extended reality (XR) virtual practical and educational eGaming to provide effective immersive environments for learning and teaching in forensic science

Online virtual learning resources have been available for learning and teaching in forensic science for some years now, but the recent global COVID-19 related periods of irregular lockdown have necessitated the rapid development of these for teaching, learning and CPD activities. However, these resources do need to be carefully constructed and grounded in pedagogic theory to be effective. This article details eXtended Reality (XR) learning and teaching environments to facilitate effective online teaching and learning for forensic geoscientists. The first two case studies discussed in this article make use of Thinglink software to produce virtual learning and teaching XR resources through an internet system, which was delivered to undergraduate students in 2021. Case one details a range of XR virtual laboratory-based equipment resources, providing a consistent, reliable and asynchronous learning and teaching experience, whilst the second case study presents an XR virtual learning applied geophysics resource developed for a 12-week CPD training programme. This programme involves recorded equipment video resources, accompanying datasets and worksheets for users to work through. Both case studies were positively received by learners, but there were issues encountered by learners with poor internet connections or computer skills, or who do not engage well with online learning. A third case study showcases an XR educational forensic geoscience eGame that was developed to take the user through a cold case search investigation, from desktop study through to field reconnaissance and multi-staged site investigations. Pedagogic research was undertaken with user questionnaires and interviews, providing evidence that the eGame was an effective learning and teaching tool. eGame users highly rated the eGame and reported that they raised awareness and understanding of the use of geophysics equipment and best practice of forensic geoscience search phased investigations. These types of XR virtual learning digital resources, whilst costly to produce in terms of development time and staff resource, provide a complementary virtual learning experience to in-situ practical sessions, and allow learners to asynchronously familiarise themselves with equipment, environments and techniques resulting in more efficient use of in situ time. The XR resources also allow learners to reinforce learning post in-situ sessions. Finally, XR resources can provide a more inclusive and authentic experience for learners who cannot attend or complete work synchronously.     

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.     

Missing persons-missing data: the need to collect antemortem dental records of missing persons

The subject of missing persons is of great concern to the community with numerous associated emotional, financial, and health costs. This paper examines the forensic medical issues raised by the delayed identification of individuals classified as "missing" and highlights the importance of including dental data in the investigation of missing persons. Focusing on Australia, the current approaches employed in missing persons investigations are outlined. Of particular significance is the fact that each of the eight Australian states and territories has its own Missing Persons Unit that operates within distinct state and territory legislation. Consequently, there is a lack of uniformity within Australia about the legal and procedural framework within which investigations of missing persons are conducted, and the interaction of that framework with coronial law procedures. One of the main investigative problems in missing persons investigations is the lack of forensic medical, particularly, odontological input. Forensic odontology has been employed in numerous cases in Australia where identity is unknown or uncertain because of remains being skeletonized, incinerated, or partly burnt. The routine employment of the forensic odontologist to assist in missing person inquiries, has however, been ignored. The failure to routinely employ forensic odontology in missing persons inquiries has resulted in numerous delays in identification. Three Australian cases are presented where the investigation of individuals whose identity was uncertain or unknown was prolonged due to the failure to utilize the appropriate (and available) dental resources. In light of the outcomes of these cases, we suggest that a national missing persons dental records database be established for future missing persons investigations. Such a database could be easily managed between a coronial system and a forensic medical institute. In Australia, a national missing persons dental records database could be incorporated into the National Coroners Information System (NCIS) managed, on behalf of Australia's Coroners, by the Victorian Institute of Forensic Medicine. The existence of the NCIS would ensure operational collaboration in the implementation of the system and cost savings to Australian policing agencies involved in missing person inquiries. The implementation of such a database would facilitate timely and efficient reconciliation of clinical and postmortem dental records and have subsequent social and financial benefits.     

Judicial responses to the protected confidential communications legislation in Australia

The article examines the background, aims and scope of recent legislation enacted in New South Wales, Victoria and South Australia to protect from disclosure in court of "confidential communications" generated in the context of counselling persons who allege that they were victims of sexual offenses. In drafting the "confidential communications" legislation, the legislators undertook a difficult task of balancing the public interest in therapeutic confidentiality that would encourage victims of sexual assaults to report these offenses and seek psychological and psychiatric care on the one hand, and the public interest in fairness of the trial, which may be prejudiced by exclusion of evidence pertinent to the forensic process on the other. In South Australia this task was fulfilled with greater success than in New South Wales and Victoria.     

Wandering Dementia—A Syndrome with Forensic Implications

Wandering behavior in dementia may result in significant injury or death. Search of files at Forensic Science South Australia over a 20‐year period (1998–2018) identified nine individuals with dementia who were found deceased having been reported as missing from home/residential facilities (M:F, 6:3; age range, 54–92 years; average, 77.7 years; median, 80 years). The established clinical diagnoses were of dementia in seven cases and Alzheimer disease in two. Deaths were unnatural in six cases: hypo/hyperthermia three, drowning two, train impact one; natural in two cases due to ischemic (N=1) and valvular heart disease (N=1); and undetermined in one case due to marked decomposition. There were five fatalities in winter. Exposure and drowning were significant causes of death. The increasing aging population means cases of lethal wandering dementia will be more often encountered among forensic cases in future. Issues around duty of care and suicide should be considered in evaluating cases.     

The current status of forensic science laboratory accreditation in Europe

Forensic science is gaining some solid ground in the area of effective crime prevention, especially in the areas where more sophisticated use of available technology is prevalent. All it takes is high-level cooperation among nations that can help them deal with criminality that adopts a cross-border nature more and more. It is apparent that cooperation will not be enough on its own and this development will require a network of qualified forensic laboratories spread over Europe. It is argued in this paper that forensic science laboratories play an important role in the fight against crime. Another, complimentary argument is that forensic science laboratories need to be better involved in the fight against crime. For this to be achieved, a good level of cooperation should be established and maintained. It is also noted that harmonization is required for such cooperation and seeking accreditation according to an internationally acceptable standard, such as ISO/IEC 17025, will eventually bring harmonization as an end result. Because, ISO/IEC 17025 as an international standard, has been a tool that helps forensic science laboratories in the current trend towards accreditation that can be observed not only in Europe, but also in the rest of the world of forensic science. In the introduction part, ISO/IEC 17025 states that "the acceptance of testing and calibration results between countries should be facilitated if laboratories comply with this international standard and if they obtain accreditation from bodies which have entered into mutual recognition agreements with equivalent bodies in other countries using this international standard." Furthermore, it is emphasized that the use of this international standard will assist in the harmonization of standards and procedures. The background of forensic science cooperation in Europe will be explained by using an existing European forensic science network, i.e. ENFSI, in order to understand the current status of forensic science in Europe better. The Council of Europe and the European Union approaches to forensic science will also be discussed by looking at the legal instruments and documents published by these two European organizations. Data collected from 52 European forensic science laboratories will be examined and findings will be evaluated from a quality assurance and accreditation point of view. The need for harmonization and accreditation in forensic science will be emphasized. The steps that should be taken at the European level for increasing and strengthening the role of European forensic science laboratories in the fight against crime will be given as recommendations in the conclusion.     

The ultrastructure of tissue attached to telogen hair roots

Most tissues encountered in forensic biology laboratories have been previously characterized with electron microscopy due to their medical importance. Anagen hair root cells, epithelial cells, erythrocytes, neutrophils, osteocytes, and spermatozoa have received considerable research attention at the ultrastructural level. There is no literature indicating that cells attached to removed telogen hair roots have been characterized with transmission electron microscopy. Nonetheless, telogen hairs are a frequent submission item to forensic laboratories for DNA typing. The amount of tissue attached to a telogen hair root usually determines whether that hair is suitable for nuclear DNA typing methods or mitochondrial DNA typing methods. This study used transmission and scanning electron microscopy to characterize the tissues found in three commonly occurring telogen hair root forms. The tissues were found to consist of keratinized remnant follicle, nonnucleated epithelial cells, nucleated epithelial cells, and trichilemmal keratin. These findings were consistent with the known principles of hair follicle regression. The recognition of the root structures that contain these specific tissue types may assist in the DNA typing of telogen hairs inasmuch as the quality of tissue present may be more important than the amounts of tissue present.     

Experimental and casework validation of ambient temperature corrections in forensic entomology

This paper expands on Archer (J Forensic Sci 49, 2004, 553), examining additional factors affecting ambient temperature correction of weather station data in forensic entomology. Sixteen hypothetical body discovery sites (BDSs) in Victoria and New South Wales (Australia), both in autumn and in summer, were compared to test whether the accuracy of correlation was affected by (i) length of correlation period; (ii) distance between BDS and weather station; and (iii) periodicity of ambient temperature measurements. The accuracy of correlations in data sets from real Victorian and NSW forensic entomology cases was also examined. Correlations increased weather data accuracy in all experiments, but significant differences in accuracy were found only between periodicity treatments. We found that a >5°C difference between average values of body in situ and correlation period weather station data was predictive of correlations that decreased the accuracy of ambient temperatures estimated using correlation. Practitioners should inspect their weather data sets for such differences.