UK Forensic Science Research Articles

Relevant propositions for Y chromosome interpretation

AbstractThe Y chromosomal haplotype is expected to be identical (or close to, depending on the mutation rate) among a male and many of his paternal relatives. This means that often the same evidential value for the DNA evidence is obtained, whether the true donor or one of his close paternal relatives is compared to a crime sample. Commentators (see for example the UK Forensic Science Regulator or Amorim) have suggested to change the proposition pair to compare the probability of the evidence if the Person of Interest (POI) or one of his close paternal relatives left the DNA to the probability of the evidence if an unrelated male from the population left the DNA. We argue that this is problematic because there is no clear definition of close paternal relatives and truly unrelated males do not exist. Instead, we take a starting point in the traditional proposition pair “The source of the male DNA is the POI” versus “The source of the male DNA is not the POI” and make the latter one operational by suggesting that it is formulated as “The source of the male DNA is a random man from the population”. The issue of matching males in the POI's lineage is then addressed either in a comment in the statement or directly through a probability model.

Interpretation and reporting of mixed DNA profiles by seven forensic laboratories in the UK and Ireland

In 2014, the UK Forensic Science Regulator (FSR) commissioned a collaborative trial to assess the methods used by forensic service providers (FSPs) in the UK and Ireland for analysis, interpretation and reporting of mixed DNA profiles. Five different mixed samples of varying complexity with supporting mock case circumstances were tested using SGMPlus™ and the newly introduced DNA-17(+) multiplexes and reported by participating laboratories. The results demonstrated a high degree of consistency in analytical methods and allele designations, but some variation in the statistical evaluation and reporting of results. Some of the differences noted were attributable to the major technology change to 17(+)-STR systems which had recently been implemented across the UK at that time. The FSR made recommendations based on the trial outcomes which were intended to produce a more consistent approach to mixtures analysis, interpretation and reporting.Four years later, the Association of Forensic Science Providers (AFSP) repeated the trial, with all major UK and Ireland FSPs (both public sector and private companies) again participating. This second trial used the same mixture set as the 2014 trial but was focussed on the methods for interpretation and evaluation. Since 2014, all UK and Ireland FSPs have implemented probabilistic statistical software using continuous models enabling statistical evaluation of more complex mixtures than was possible in 2014. The trial was therefore aimed at investigating the value of these improved capabilities and also to investigate if there appeared to be marked differences between the different software tools in use in the UK.The results demonstrate a high degree of concordance within and between FSPs and across different evaluation models, and will provide important support for the use of such models in evaluation of mixed DNA profiles.

Interpretation of DNA data within the context of UK forensic science — investigation

This article is the second part of a review of the interpretation of DNA data in forensic science. The first part describes the evaluation of autosomal profile for criminal trials where an evidential weight is assigned to the profile of a person of interest (POI) and a crime-scene profile. This part describes the state of the art and future advances in the interpretation of forensic DNA data for providing intelligence information during an investigation. Forensic DNA is crucial in the investigative phase of an undetected crime where a POI needs to be identified. A sample taken from a crime scene is profiled using a range of forensic DNA tests. This review covers investigation using autosomal profiles including searching national and international crime and reference DNA databases. Other investigative methodologies described are kinship analysis; familial searching; Y chromosome (Y-STR) and mitochondrial (mtDNA) profiles; appearance prediction and geographic ancestry; forensic genetic genealogy; and body identification. For completeness, the evaluation of Y-STRs, mtDNA and kinship analysis are briefly described. Taken together, parts I and II, cover the range of interpretation of DNA data in a forensic context.

Interpretation of DNA data within the context of UK forensic science - evaluation.

Forensic DNA provides a striking contribution to the provision of justice worldwide. It has proven to be crucial in the investigative phase of an unsolved crime where a suspect needs to be identified, e.g. from a DNA database search both nationally and internationally. It is also a powerful tool in the assignment of evidential weight to the comparison of a profile of a person of interest and a crime scene profile. The focus of this document is the evaluation of autosomal profiles for criminal trials in the UK. A separate review covers investigation and evaluation of Y-STR profiles, investigation using autosomal profiles, kinship analysis, body identification and Forensic Genetic Genealogy investigations. In less than 40 years, forensic DNA profiling has developed from a specialist technique to everyday use. Borrowing on advances in genome typing technology, forensic DNA profiling has experienced a substantial increase in its sensitivity and informativeness. Alongside this development, novel interpretation methodologies have also been introduced. This document describes the state of the art and future advances in the interpretation of forensic DNA data.

Standardization of forming and expressing preliminary evaluative opinions on digital evidence

The growing number of cases involving overlooked or misinterpreted digital evidence is raising concerns among factfinders and decision-makers about the reliability of digital forensic conclusions. To reduce the risk of mistakes and misinterpretations of forensic observations, including but not limited to digital evidence, there is a pressing need to standardize how evaluative opinions are formed and expressed. Responding to this need, the international community is drafting ISO-21043 and the UK Forensic Science Regulator is drafting an evaluative interpretation standard that promote a likelihood ratio approach. This approach is suitable for fully evaluative opinions in many forensic disciplines, but until more refined methods for evaluating digital evidence are developed, digital forensic practitioners require an interim solution to address immediate needs. More broadly, digital evidence is used in many non-judicial contexts that do not require fully evaluative opinions expressed as a likelihood ratio. This work proposes a standardized approach to formulating and expressing preliminary evaluative opinions in terms of strength of evidence in a manner that employs scientific reasoning within a logical Bayesian framework and can be understood by non-specialist factfinders. Illustrative case examples are presented that involve digital evidence tampering. In addition, this work presents a proof-of-concept database of cases involving tampering of digital evidence that could support assignment of strength of evidence in similar cases.

The impact of Brexit on the future of UK forensic science and technology

This article seeks to assess the prospects of UK forensic science and technology in a post-Brexit world by analysing four interlocking issues: Brexit itself, the evolution of national criminal justice organisational and funding priorities, the increasing interrelationship of science and technology in the forensic domain and the relatively disadvantaged place of forensic science and technology within the contemporary ‘scientific state’ paradigm. The results are generally pessimistic for the likely future of forensic science. This conclusion is reinforced by scepticism about the wisdom of proceeding with Brexit. The article is structured to identify the potential implications of British political decisions on its national forensic science capabilities and capacity. Some aspects of the analysis are likely to have a wider resonance for international discourse about the future sustainability of forensic science and technology, however, particularly the interface between the globalisation of science and technology with justice.

What do forensic analysts consider relevant to their decision making?

In response to research demonstrating that irrelevant contextual information can bias forensic science analyses, authorities have increasingly urged laboratories to limit analysts' access to irrelevant and potentially biasing information (Dror and Cole (2010) [3]; National Academy of Sciences (2009) [18]; President's Council of Advisors on Science and Technology (2016) [22]; UK Forensic Science Regulator (2015) [26]). However, a great challenge in implementing this reform is determining which information is task-relevant and which is task-irrelevant. In the current study, we surveyed 183 forensic analysts to examine what they consider relevant versus irrelevant in their forensic analyses. Results revealed that analysts generally do not regard information regarding the suspect or victim as essential to their analytic tasks. However, there was significant variability among analysts within and between disciplines. Findings suggest that forensic science disciplines need to agree on what they regard as task-relevant before context management procedures can be properly implemented. The lack of consensus about what is relevant information not only leaves room for biasing information, but also reveals foundational gaps in what analysts consider crucial in forensic decision making.

THE FORENSIC CHALLENGE

This article investigates what might be characterised as “the forensic challenge” for criminal adjudication and clarifies its nature and scope. The “challenge” identified is complex, dynamic and multifaceted, encompassing a variety of issues and debates concerning the ways in which forensic science evidence is validated, generated, presented, tested, evaluated and utilised in criminal proceedings. Common law evidentiary principles governing the admissibility of scientific evidence and expert witness testimony are reviewed and the underlying assumptions and potential weaknesses of adversarial trial procedure are critically considered. The discussion is pitched at the generic level of recurring intellectual puzzles, institutional design, regulatory frameworks, procedural structures and processes, macro-policy choices and methodological prescriptions, with the intention of making it relevant to an international audience. Aspects of the procedural law and adjudicative practice of England and Wales, and the regulatory context of UK forensic science, are offered as concrete illustrations with the potential for illuminating comparative extrapolation to other legal systems. In conclusion, the article draws out specific implications for Chinese scholarship, law reform and policymaking in relation to scientific and other expert evidence, and advances a bold suggestion for entertaining an unconventionally expansive conception of “forensic science” and, correspondingly, of the challenges it presents.

Making forensic science fit for justice

This article presents a theoretically sophisticated but practically-orientated overview of the challenges of making forensic science ‘fit for’ the administration of criminal justice. A tripartite analytical structure is elucidated, comprising (1) normative foundations; (2) institutional frameworks; and (3) intellectual resources. Expounding this heuristic, scientific evidence is shown to contribute to the (always fragile) legitimacy of criminal adjudication by bolstering the law’s claims to epistemic rationality, within a broader normative framework in which considerations of justice take precedence over accurate fact-finding. Recent developments in UK forensic science policy and practice are then summarized and critically evaluated by way of comparative illustration; and it is argued that technologies of data interpretation and evidence production and transmission should be regarded as central unifying themes in any coherent conception of forensic science as an integrated field of inquiry and practice. Some practical suggestions for promoting this project are advanced. Finally, the wider implications of thinking about the fitness of forensic science for the administration of justice, as a routine activity, are directly related to forensic scientists’ professional responsibilities and the demands of intelligent policy-making in forensic science.

Cold Case Reviews of Serious Sexual Offenders: An Exploration of Pre- and Post-Index Offending Patterns

This exploratory study investigates offending patterns of perpetrators of serious sexual assaults (SSA) who were not initially identified at the time of the offense. Thirty-eight adult male offenders were identified through Operation Advance, a phased approach program that forensically reviewed historical sexual offense cases submitted to the UK Forensic Science Service during 1989 to 1999. Results indicated that approximately one-third of the SSA offenders received a post-offense conviction for a sexual‐contact offense. Results showed greater chronicity and versatility of the subsequent offenses for those younger index offenders. Explanations for the findings are discussed with implications for suspect prioritization.

Genotyping and interpretation of STR-DNA: Low-template, mixtures and database matches—Twenty years of research and development

The introduction of Short Tandem Repeat (STR) DNA was a revolution within a revolution that transformed forensic DNA profiling into a tool that could be used, for the first time, to create National DNA databases. This transformation would not have been possible without the concurrent development of fluorescent automated sequencers, combined with the ability to multiplex several loci together. Use of the polymerase chain reaction (PCR) increased the sensitivity of the method to enable the analysis of a handful of cells. The first multiplexes were simple: ‘the quad’, introduced by the defunct UK Forensic Science Service (FSS) in 1994, rapidly followed by a more discriminating ‘six-plex’ (Second Generation Multiplex) in 1995 that was used to create the world's first national DNA database. The success of the database rapidly outgrew the functionality of the original system – by the year 2000 a new multiplex of ten-loci was introduced to reduce the chance of adventitious matches. The technology was adopted world-wide, albeit with different loci. The political requirement to introduce pan-European databases encouraged standardisation – the development of European Standard Set (ESS) of markers comprising twelve-loci is the latest iteration. Although development has been impressive, the methods used to interpret evidence have lagged behind. For example, the theory to interpret complex DNA profiles (low-level mixtures), had been developed fifteen years ago, but only in the past year or so, are the concepts starting to be widely adopted. A plethora of different models (some commercial and others non-commercial) have appeared. This has led to a confusing ‘debate’ about the ‘best’ to use. The different models available are described along with their advantages and disadvantages. A section discusses the development of national DNA databases, along with details of an associated controversy to estimate the strength of evidence of matches. Current methodology is limited to searches of complete profiles – another example where the interpretation of matches has not kept pace with development of theory. STRs have also transformed the area of Disaster Victim Identification (DVI) which frequently requires kinship analysis. However, genotyping efficiency is complicated by complex, degraded DNA profiles. Finally, there is now a detailed understanding of the causes of stochastic effects that cause DNA profiles to exhibit the phenomena of drop-out and drop-in, along with artefacts such as stutters. The phenomena discussed include: heterozygote balance; stutter; degradation; the effect of decreasing quantities of DNA; the dilution effect.

Familial searching: A specialist forensic DNA profiling service utilising the National DNA Database® to identify unknown offenders via their relatives—The UK experience

The National DNA Database (NDNAD) of England and Wales was established on April 10th 1995. The NDNAD is governed by a variety of legislative instruments that mean that DNA samples can be taken if an individual is arrested and detained in a police station. The biological samples and the DNA profiles derived from them can be used for purposes related to the prevention and detection of crime, the investigation of an offence and for the conduct of a prosecution. Following the South East Asian Tsunami of December 2004, the legislation was amended to allow the use of the NDNAD to assist in the identification of a deceased person or of a body part where death has occurred from natural causes or from a natural disaster. The UK NDNAD now contains the DNA profiles of approximately 6 million individuals representing 9.6% of the UK population. As the science of DNA profiling advanced, the National DNA Database provided a potential resource for increased intelligence beyond the direct matching for which it was originally created. The familial searching service offered to the police by several UK forensic science providers exploits the size and geographic coverage of the NDNAD and the fact that close relatives of an offender may share a significant proportion of that offender's DNA profile and will often reside in close geographic proximity to him or her. Between 2002 and 2011 Forensic Science Service Ltd. (FSS) provided familial search services to support 188 police investigations, 70 of which are still active cases. This technique, which may be used in serious crime cases or in 'cold case' reviews when there are few or no investigative leads, has led to the identification of 41 perpetrators or suspects. In this paper we discuss the processes, utility, and governance of the familial search service in which the NDNAD is searched for close genetic relatives of an offender who has left DNA evidence at a crime scene, but whose DNA profile is not represented within the NDNAD. We discuss the scientific basis of the familial search approach, other DNA-based methods for eliminating individuals from the candidate lists generated by these NDNAD searches, the value of filtering these lists by age, ethnic appearance and geography and the governance required by the NDNAD Strategy Board when a police force commissions a familial search. We present the FSS data in relation to the utility of the familial searching service and demonstrate the power of the technique by reference to casework examples. We comment on the uptake of familial searching of DNA databases in the USA, the Netherlands, Australia, and New Zealand. Finally, following the adverse ruling by the European Court of Human Rights against the UK in regard to the S & Marper cases and the consequent introduction of the Protection of Freedoms Act (2012), we discuss the impact that changes to regulations concerning the storage of DNA samples will have on the continuing provision of familial searching of the National DNA Database in England and Wales.

UK forensic science slammed by inquiry

UK forensic science slammed by inquiry

Criminal Justice, Science and the Marketplace: The Closure of the Forensic Science Service in Perspective

Despite hesitant beginnings the Forensic Science Service (FSS) prospered institutionally, as the dominant supplier of forensic science services to the police, after the introduction of neoliberal policies. This ended when the FSS overreached itself and the intensification of neoliberal policies created an incongruity between its organisational objectives and those of its clients. The fortunes of UK forensic science and the FSS diverged long before its closure. Academic and learned society evidence to a Select Committee inquiry into this event, and the influence that this had on the Committee's report, illustrates this change. This expert testimony also explains the importance of the normative, epistemic and professional aspirations of criminal justice practitioners for ensuring the value of forensic science to criminal justice. We argue that the risks threatening scientific evidence, particularly recurrent problems of under-funding and unequal access for the defence, may be masked by older narratives of neoliberalism or too narrow an institutional focus.

Consideration of the probative value of single donor 15-plex STR profiles in UK populations and its presentation in UK courts

The adoption of new 15 locus STR multiplex systems into UK forensic science would be facilitated by agreed guidelines for reporting the strength of DNA evidence using likelihood ratios. To facilitate such an agreement, we present an analysis of previously published UK allele frequencies for white Caucasian, Afro-Caribbean and Indo-Pakistani populations and investigate their effect on likelihood ratios for single donor profiles. We consider the implication of the five additional loci and suggest a procedure for reporting likelihood ratios for 15-plex STR profiles.

Consideration of the probative value of single donor 15-plex STR profiles in UK populations and its presentation in UK courts II

The adoption of new 15 locus STR multiplex systems into UK forensic science would be facilitated by agreed guidelines for reporting the strength of DNA evidence using likelihood ratios. To facilitate such an agreement, we present an analysis of previously published UK allele frequencies for white Caucasian, Afro-Caribbean and Indo-Pakistani populations and investigate their effect on likelihood ratios for single donor profiles. We consider the implication of the five additional loci and suggest a procedure for reporting likelihood ratios for 15-plex STR profiles.

Are UK undergraduate Forensic Science degrees fit for purpose?

In October 2009 Skills for Justice published the social research paper 'Fit for purpose?: Research into the provision of Forensic Science degree programmes in UK Higher Education Institutions.' The research engaged employers representing 95% of UK Forensic Science providers and 79% of UK universities offering Forensic Science or Crime Scene degree programmes. In addition to this, the research collected the views of 430 students studying these degrees. In 2008 there were approximately 9000 people working in the Forensic Science sector in the UK. The research found that the numbers of students studying Forensic Science or Crime Scene degrees in the UK have more than doubled since 2002-03, from 2191 in to 5664 in 2007-08. Over the same period there were twice as many females as males studying for these degrees. The research concluded that Forensic Science degree programmes offered by UK universities were of a good quality and they provided the student with a positive learning experience but the content was not relevant for Forensic Science employers. This echoed similar research by the former Government Department for Innovation, Universities and Skills on graduates from wider science, technology, engineering and mathematics degree programmes. The research also found that 75% of students studying Forensic Science or Crime Scene degrees expected to have a career in the Forensic Science sector, meaning that ensuring these courses are relevant for employers is a key challenge for universities. This paper reflects on the original research and discusses the implications in light of recent government policy.

Helping with inquiries or helping with profits? The trials and tribulations of a technology of forensic reasoning

The commercialization of forensic scientific provision in the UK over the last two decades has had a major role in shaping a changing epistemic identity for forensic scientists working within this jurisdiction. Efforts to match the presumed epistemological standards of the 'pure' sciences have been brought together with concerns about value for money in a new approach to the interpretation of evidence, an activity that lies at the heart of criminal investigative practice. A study of the Case Assessment and Interpretation method developed by members of the UK Forensic Science Service is used to show how a technical innovation in the delivery of forensic science services to the police has instantiated these two recent social processes.

The Future of Forensic and Crime Scene Science: Part I. A UK forensic science user and provider perspective

This paper presents an overview of the views expressed by UK forensic science users and providers during the Centre for Forensic Investigation's 1 day conference ‘The Future of Forensic and Crime Scene Science’ and is set in the context of the changing national agenda and likely advances in current and future technology. It begins by examining the success of the Home Office DNA Expansion Programme and future demands of the Criminal Justice System, highlighting the changing use of forensic science both at the crime scene and within the forensic process itself. In particular, the use of forensic science at the early stages of an investigation to provide intelligence and support the decision making process is discussed together with the need to adopt a partnership approach to tackling crime and its causes. Key system and technological drivers for performance improvement and change are identified and the likely timescales and implications of their introduction are discussed. Finally, the Home Office plans to build on the success of the DNA Expansion Programme, through the introduction of the proposed Home Office Forensic Integration Strategy, are explored and the paper concludes by highlighting the benefits, implications and issues arising from the changing and developing use of forensic science.

D.N.A. Databases and Property Crime: A False Promise?

This article examines the potential for the Australian national criminal deoxyribonucleic acid (DNA) database in its application to high volume property crimes, such as burglaries and motor vehicle thefts, and is based primarily on UK data. The potential capacity for police to achieve convictions from reported property offences, and to lower crime levels, was assessed by analysing UK Forensic Science Service and Police inspection reports. The UK national criminal DNA database was selected for examination, as it is the world's longest established and claims the highest “match” rate. It was found that after the database had been in operation for more than seven years it was responsible on average for achieving convictions in close to one percent of reported burglaries, a figure that included the additional convictions developed from the intelligence that the database provided. Having funded a DNA regime from public monies, it may be time for policymakers in Australia to critically reassess expectations for the impact that DNA databases may have on volume crime levels and to focus efforts on those crimes most likely to be solved by the application of DNA testing.