Assessment of approximate likelihood ratios from continuous distributions: a case study of digital camera identification

A reported likelihood ratio for the value of evidence is very often a point estimate based on various types of reference data. When presented in court, such frequentist likelihood ratio gets a higher scientific value if it is accompanied by an error bound. This becomes particularly important when the magnitude of the likelihood ratio is modest and thus is giving less support for the forwarded proposition. Here, we investigate methods for error bound estimation for the specific case of digital camera identification. The underlying probability distributions are continuous and previously proposed models for those are used, but the derived methodology is otherwise general. Both asymptotic and resampling distributions are applied in combination with different types of point estimators. The results show that resampling is preferable for assessment based on asymptotic distributions. Further, assessment of parametric estimators is superior to evaluation of kernel estimators when background data are limited.     

Two or three contributors of DNA mixtures? – Some practical considerations

The number of contributors is hard to determine in DNA mixture profiles. Here, we deal with the special but frequent case that either two or three contributors are possible. In fact, it might happen that two contributors can explain the number of alleles seen but that three contributors are necessary if a specific person of interest is to be included in the mixture. Then the likelihood ratio assuming two contributors will be zero while the likelihood ratio for three contributors may be large. We evaluate this situation and offer suggestions on how to arrive at an overall likelihood ratio. To exemplify our line of reasoning we use an example proposed by Biedermann, Taroni and Thompson.     

An Objective Corruption Risk Index Using Public Procurement Data

In order to address the lack of reliable indicators of corruption, this article develops a composite indicator of high-level institutionalised corruption through a novel ‘Big Data’ approach. Using publicly available electronic public procurement records in Hungary, we identify “red flags” in the public procurement process and link them to restricted competition and recurrent contract award to the same company. We use this method to create a corruption indicator at contract level that can be aggregated to the level of individual organisations, sectors, regions and countries. Because electronic public procurement data is available in virtually all developed countries from about the mid-2000s, this method can generate a corruption index based on objective data that is consistent over time and across countries. We demonstrate the validity of the corruption risk index by showing that firms with higher corruption risk score had relatively higher profitability, higher ratio of contract value to initial estimated price, greater likelihood of politicians managing or owning them and greater likelihood of registration in tax havens, than firms with lower scores on the index. In the conclusion we discuss the uses of this data for academic research, investigative journalists, civil society groups and small and medium business.     

Bloodstain pattern analysis & Bayes: A case report

The findings from a bloodstain pattern analysis (BPA) may assist in formulating or falsifying scenarios that are considered in the investigative stages of a criminal investigation. When a case proceeds to trial the bloodstain pattern expert may be asked about the relevance of their findings given scenarios that are proposed by the prosecution and defense counsel. Such opinions provided by an expert are highly relevant to police investigation or legal proceedings, but the reasoning behind the opinion or implicit assumptions made by the expert may not be transparent.A proper framework for the evaluation of forensic findings has been developed since the late twentieth century, based on the hierarchy of propositions, Bayesian reasoning and a model for case assessment and interpretation. This framework, when implemented in casework, mitigates some of the risks of cognitive biases, and makes the reasoning and scientific basis for the opinion transparent. This framework is broadly used across forensic science disciplines. In this paper we describe its application to the field of BPA using a case example from the Netherlands Forensic Institute (NFI).     

Contemporary criminal defence practice: importance of active involvement at the investigative stage and related training requirements

ABSTRACT

The shifting focus of criminal proceedings from the trial to the pre-trial stages leads to a changing role of criminal defence practitioners across Europe. European criminal defence lawyers are now expected to enter the proceedings earlier and exercise “active” and “participatory” defence as early as the investigative stage. Criminal lawyers, trained in the traditional trial-centred paradigm, are ill-prepared for this role, which results in an important skills gap. Legal representation at the investigative stage presents unique challenges, such as shortage of information, time pressures and the closed nature of pre-trial proceedings. It requires lawyers to operate in a more complex communication environment, than the one to which they have been accustomed. This article sets out the main elements of a professional training programme aiming to fill in the emerging skills gap. The training programme (SUPRALAT) was successfully implemented in Belgium, Hungary, Ireland and the Netherlands, and is being expanded further. The training focuses on effective communication skills, experiential learning and the development of reflective skills. It includes elements of interprofessional training and encourages the development of “communities of practice”.     

Trial and Error – Failing and Learning in Criminal Proceedings

This paper addresses the selective mechanisms by which criminal proceedings produce strong arguments. It does so by focusing on the failing of argument themes (topoi) in the course of criminal proceedings, rather than on their career. In a further step, the notion of failing is bound to learning: different forms of failing point at different ways and places of learning. The study is comparative, relating cases from four different legal regimes (England, USA, Italy and Germany) that are taken from four extensive ethnographic studies in defense lawyer’s firms. We will track down the failures of topoi at three different stages (pre-trial, trial, and deliberation) in our different legal regimes. Failing occurs in all proceedings in various modes and at different stages. We argue that those modes as well as the different stages at which they occur point at the spots in the respective procedures that allow for learning about the inherent conceptions of “good reasons.”     

Digital traces and physical activities: opportunities,challenges and pitfalls

The strong integration of consumer electronics in everyday life offers many new investigative opportunities. In particular, digital traces from smartphones, smartwatches and activity trackers can now increasingly be used to infer information about actions performed by their users in the physical world that might not be obtainable from any other types of forensic evidence.While potentially very valuable from an investigative perspective, making forensically justifiable statements about such traces can sometimes be more difficult than expected. Requirements for this have not yet received much attention in the digital forensic literature. To help filling this gap, we describe the principles we use in determining the evidential value of such traces, which emphasize the need for experimental verification. For such research, aimed at determining the evidential value of these traces, we coin the term data2activity.In this paper, we devote attention to the potential and limitations of data2activity traces, focusing on challenges and giving two examples to illustrate potential pitfalls in interpreting data. Finally, future research directions into data2activity traces are indicated that, in our opinion, should be given attention. These include development of future-proof data acquisition and storage methodology, enabling division-of-effort and sharing of information, as well as development of labeling methodology for free-living experiments.     

Comparative vs. Transcendental Approaches to Justice: A Misleading Dichotomy in Sen's The Idea of Justice

This paper examines the distinction drawn by Amartya Sen between transcendental and comparative theories of justice, and its application to Rawls' doctrine. It then puts forward three arguments. First, it is argued that Sen offers a limited portrayal of Rawls' doctrine. This is the result of a rhetorical strategy that depicts Rawlsian doctrine as more “transcendental” than it really is. Although Sen deploys numerous quotations in support of his interpretation, it is possible to offer a less transcendental interpretation of Rawls. Second, the dichotomy between transcendental and comparative approaches to questions of justice is partly misleading, insofar as any plausible moral doctrine has both transcendental and comparative elements. Transcendental elements are necessary to avoid the confusion between the general acceptance of a norm, value or principle and its justification. A comparative view highlights the conditions of application of the doctrine to the real world, taking into account the possibility of moral dilemmas, evaluative disagreements and limited resources, while proposing possible provisos and caveats to the risk of the doctrine being self‐defeating. Third, although the transcendental approach is useful, it is argued that in elaborating this dichotomy Sen overlooks the merits of the third way between comparative and transcendental doctrines, what he calls “conglomerate theory,” and also the possibility that his doctrine (the capability approach) might be considered as an example of such a theory. The paper concludes with the argument that conglomerate theory does not aim to produce complete moral orderings, but rather a comparative approach with transcendental elements, as a form of weak transcendentalism.     

The Role of Suggestibility in Personal Injury Claims

Interrogative suggestibility and other psychological vulnerabilities are often assessed in the forensic criminal context in disputed confession cases. Such an assessment may also be relevant in disputing the validity of a confession by a plaintiff in a tort claim. This paper will outline the relevancy of suggestibility in the personal injury context, the reasons why an individual may falsely confess, how interrogative techniques may increase the likelihood of a false confession, false confession and suggestibility research, and methodology to be used in assessing vulnerability to falsely confessing.     

Crimes Against Humanity and the Limits of International Criminal Law

Crimes against humanity are supposed to have a collective dimension with respect both to their victims and their perpetrators. According to the orthodox view, these crimes can be committed by individuals against individuals, but only in the context of a widespread or systematic attack against the group to which the victims belong. In this paper I offer a new conception of crimes against humanity and a new justification for their international prosecution. This conception has important implications as to which crimes can be justifiably prosecuted and punished by the international community. I contend that the scope of the area of international criminal justice that deals with basic human rights violations should be wider than is currently acknowledged, in that it should include some individual violations of human rights, rather than only violations that have a collective dimension.     

The International Crimes Tribunal in Bangladesh and International Law

The International Crimes Tribunal in Bangladesh was re-established in 2010 in order to hold the perpetrators of the 1971 War accountable for international crimes; namely, war crimes, crimes against humanity and genocide. The Trial has already begum to operate and has been dealing with various challenges. The basis of the trial proceedings is the International Crimes (Tribunal) Act 1973. The Parliament of Bangladesh enacted the Act in accordance with international law shortly after the War. This paper assesses the key legal issues that arise from the context of the 1973 Act, and will provide a reflection on trial proceedings in light of international law. It concludes that any initiatives to address the impunity of perpetrators and offer redress to the victims of gross human rights violations should be applauded, while any trial proceedings that do not follow appropriate standards for a fair trial and offer the right of due process should be deprecated.     

Using subsampling to estimate the strength of handwriting evidence via score-based likelihood ratios

The likelihood ratio paradigm has been studied as a means for quantifying the strength of evidence for a variety of forensic evidence types. Although the concept of a likelihood ratio as a comparison of the plausibility of evidence under two propositions (or hypotheses) is straightforward, a number of issues arise when one considers how to go about estimating a likelihood ratio. In this paper, we illustrate one possible approach to estimating a likelihood ratio in comparative handwriting analysis. The novelty of our proposed approach relies on generating simulated writing samples from a collection of writing samples from a known source to form a database for estimating the distribution associated with the numerator of a likelihood ratio. We illustrate this approach using documents collected from 432 writers under controlled conditions.     

法治视野中的刑事案件立案程序——以公安机关为视角的考证

刑事立案程序是刑事诉讼的启动程序和开展刑事侦查的必经程序,公安机关作为刑事案件侦查的主力军,其立案、侦查职权具有专属性和排他性,但是,公安机关在侦办刑事案件中的立案程序却存在立案标准不统一、立案标准缺失、立案与撤案法律依据相互矛盾等诸多缺憾,极易造成基层职能部门的无所适从乃至变相操作,应当从统一立案标准、加强对侦查活动的监督制约等多方面去完善侦查活动的构造,以修葺立案程序的法治化出路。     

A review of major factors contributing to errors in human hair association by microscopy.

Forensic hair examiners using traditional microscopic comparison techniques cannot state with certainty, except in extremely rare cases, that a found hair originated from a particular individual. They also cannot provide a statistical likelihood that a hair came from a certain individual and not another. There is no data available regarding the frequency of a specific microscopic hair characteristic (i.e., microtype) or trait in a particular population. Microtype is a term we use to describe certain internal characteristics and features expressed when observing hairs with unpolarized transmitted light. Courts seem to be sympathetic to lawyer's concerns that there are no accepted probability standards for human hair identification. Under Daubert, microscopic hair analysis testimony (or other scientific testimony) is allowed if the technique can be shown to have testability, peer review, general acceptance, and a known error rate. As with other forensic disciplines, laboratory error rate determination for a specific hair comparison case is not possible. Polymerase chain reaction (PCR)-based typing of hair roots offer hair examiners an opportunity to begin cataloging data with regard to microscopic hair association error rates. This is certainly a realistic manner in which to ascertain which hair microtypes and case circumstances repeatedly cause difficulty in association. Two cases are presented in which PCR typing revealed an incorrect inclusion in one and an incorrect exclusion in another. This paper does not suggest that such limited observations define a rate of occurrence. These cases illustrate evidentiary conditions or case circumstances which may potentially contribute to microscopic hair association errors. Issues discussed in this review paper address the potential questions an expert witness may expect in a Daubert hair analysis admissibility hearing.     

Inclusiveness, Effectiveness and Intrusiveness: Issues in the Developing Uses of DNA Profiling in Support of Criminal Investigations

The rapid implementation and continuing expansion of forensic DNA databases around the world has been supported by claims about their effectiveness in criminal investigations and challenged by assertions of the resulting intrusiveness into individual privacy. These two competing perspectives provide the basis for ongoing considerations about the categories of persons who should be subject to non-consensual DNA sampling and profile retention as well as the uses to which such profiles should be put. This paper uses the example of the current arrangements for forensic DNA databasing in England and Wales to discuss the ways in which the legislative and operational basis for police DNA databasing is reliant upon continuous deliberations over these and other matters by a range of key stakeholders. We also assess the effects of the recent innovative use of DNA databasing for "familial searching" in this jurisdiction in order to show how agreed understandings about the appropriate uses of DNA can become unsettled and reformulated even where their investigative effectiveness is uncontested. We conclude by making some observations about the future of what is recognized to be the largest forensic DNA database in the world.     

Species identification of Papaver by metabolite profiling

This paper analyses and discusses arguments that emerge from a recent discussion about the proper assessment of the evidential value of correspondences observed between the characteristics of a crime stain and those of a sample from a suspect when (i) this latter individual is found as a result of a database search and (ii) remaining database members are excluded as potential sources (because of different analytical characteristics). Using a graphical probability approach (i.e., Bayesian networks), the paper here intends to clarify that there is no need to (i) introduce a correction factor equal to the size of the searched database (i.e., to reduce a likelihood ratio), nor to (ii) adopt a propositional level not directly related to the suspect matching the crime stain (i.e., a proposition of the kind 'some person in (outside) the database is the source of the crime stain' rather than 'the suspect (some other person) is the source of the crime stain'). The present research thus confirms existing literature on the topic that has repeatedly demonstrated that the latter two requirements (i) and (ii) should not be a cause of concern.     

Prior Police Contact and Subsequent Victim Reporting: Results from the NCVS

This study investigated the association between victim reporting and the police response to past victimizations with data from the National Crime Victimization Survey from 1998–2000. The findings include: (1) investigatory effort by police when an individual had been victimized in the past increased the likelihood that the individual would report an ensuing victimization to the police; (2) however, this relationship only held when the victim, rather than someone else, reported the prior victimization to the police; (3) whether the police made an arrest after an individual was victimized in the past had no effect on whether the individual reported an ensuing victimization to the police; (4) the probability of victim reporting was unaffected by investigatory effort or whether an arrest was made after a prior victimization of a member of the victim’s household.     

Case based reasoning in criminal intelligence using forensic case data.

A model that is based on the knowledge of experienced investigators in the analysis of serial crime is suggested to bridge a gap between technology and methodology. Its purpose is to provide a solid methodology for the analysis of serial crimes that supports decision making in the deployment of resources, either by guiding proactive policing operations or helping the investigative process. Formalisation has helped to derive a computerised system that efficiently supports the reasoning processes in the analysis of serial crime. This novel approach fully integrates forensic science data.     

The social ecology of homicide: A modified lifestyle/routine activities perspective

Recent research on criminal victimization suggests that lifestyle may offer important insights into the unequal distribution of crime. The lifestyle approach is used here to explore variations in homicide rates for Dade County, Florida. The application of this approach to the analysis of cross-sectional variations in homicide rates requires (1) elaboration of the assumptions that connect the likelihood of victimization for individuals to variations in the rate of victimization by location as well as (2) justification of the selection of specific variables as indicators of variation in exposure to the risk of homicide. In sum, four individual characteristics and six residential characteristics are said to be implicated in the explanation of variations in homicide rates among census tracts. Census tract data derived from 1980 Bureau of Census files are used to explore these variations. Findings suggest that future researchers should consider the relative importance of individual attributes, especially marital status, in increasing the risk of homicide victimization.