A forensic science perspective on the role of images in crime investigation and reconstruction

This article presents a global vision of images in forensic science. The proliferation of perspectives on the use of images throughout criminal investigations and the increasing demand for research on this topic seem to demand a forensic science-based analysis. In this study, the definitions of and concepts related to material traces are revisited and applied to images, and a structured approach is used to persuade the scientific community to extend and improve the use of images as traces in criminal investigations. Current research efforts focus on technical issues and evidence assessment. This article provides a sound foundation for rationalising and explaining the processes involved in the production of clues from trace images. For example, the mechanisms through which these visual traces become clues of presence or action are described. An extensive literature review of forensic image analysis emphasises the existing guidelines and knowledge available for answering investigative questions (who, what, where, when and how). However, complementary developments are still necessary to demystify many aspects of image analysis in forensic science, including how to review and select images or use them to reconstruct an event or assist intelligence efforts. The hypothetico-deductive reasoning pathway used to discover unknown elements of an event or crime can also help scientists understand the underlying processes involved in their decision making. An analysis of a single image in an investigative or probative context is used to demonstrate the highly informative potential of images as traces and/or clues. Research efforts should be directed toward formalising the extraction and combination of clues from images. An appropriate methodology is key to expanding the use of images in forensic science.     

Identifying and measuring juror pre-trial bias for forensic evidence: development and validation of the Forensic Evidence Evaluation Bias Scale

Abstract

Previous research has provided support for the impact of juror pre-trial bias on judicial decision making, particularly in cases where the evidence presented at trial is of weak or ambiguous probative value. In an effort to identify whether a pre-trial bias for forensic evidence exists, the Forensic Evidence Evaluation Bias Scale (FEEBS) was developed and tested. The results of a principal components analysis suggested that two distinct constructs were being measured, corresponding to a pro-prosecution and pro-defence bias toward forensic evidence. In a second validation study, scores on these two subscales were compared with other existing juror bias measures (Juror Bias Scale and Belief in a Just World) and in a mock juror decision making task only the pro-prosecution subscale of the FEEBS predicted the perceived strength of forensic evidence. A partial mediation model is presented which explains the relationship between this bias and verdict preferences. The implications of this potential juror bias are discussed in the context of real juries, the CSI Effect (which refers to anecdotal claims that jurors are biased by the popularity of fictional representations of forensic science on television) and peremptory challenges, as well as future research directions.     

A cultural change to enable improved decision-making in forensic science: A six phased approach

There has been an increased engagement by researchers in understanding the decision-making processes that occur within forensic science. There is a rapidly growing evidence base underpinning our understanding of decision-making and human factors and this body of work is the foundation for achieving truly improved decision-making in forensic science. Such an endeavour is necessary to minimise the misinterpretation of scientific evidence and maximize the effectiveness of crime reconstruction approaches and their application within the criminal justice system. This paper proposes and outlines a novel six phased approach for how a broadening and deepening knowledge of decision-making in forensic science can be articulated and incorporated into the spheres of research, practice, education, and policy making within forensic science specifically, and the criminal justice system more generally. Phases 1 and 2 set out the importance of systematic examination of the decisions which play a role throughout forensic reconstruction and legal processes. Phase 3 focuses on how these decisions can, and should, be studied to understand the underlying mechanisms and contribute to reducing the occurrence of misleading decisions. Phase 4 highlights the ways in which the results and implications of this research should be communicated to the forensic community and wider criminal justice system. Lastly, the way in which the forensic science domain can move forwards in managing the challenges of human decision-making and create and embed a culture of acceptance and transparency in research, practice and education (learning and training) are presented in phases 5 and 6. A consideration of all 6 connected phases offers a pathway for a holistic approach to improving the transparency and reproducibility of decision making within forensic science.     

Value of DNA tests: a decision perspective

ABSTRACT: Before a Court of Law testifying in DNA‐evidence cases, scientists are often challenged with the idea that the more markers (loci) the better, i.e., why does the scientist not use 16 or more markers? This paper introduces a new perspective, decision analysis, to deal with the problem of the number of markers to type in a criminal context. The decision‐making process, which plays a key role in the routine work of a forensic scientist, consists of the rational choice, given personal objectives, between two or more possible outcomes when the consequences of the choice are uncertain. Simulated results support the hypothesis that analytical added value does not increase with the number of markers.     

Naturalistic decision making in forensic science: toward a better understanding of decision making by forensic team leaders

This study uses the naturalistic decision-making (NDM) perspective to examine how Dutch forensic team leaders (i.e., the officers in charge of criminal forensic research from the crime scene until the use of laboratory assistance) make decisions in real-life settings and identifies the contextual factors that might influence those decisions. First, a focus group interview was conducted to identify four NDM mechanisms in day-to-day forensic decision making. Second, a serious game was conducted to examine the influence of three of these contextual mechanisms. The results uncovered that forensic team leaders (i) were attracted to obtain further information when more information was initially made available, (ii) were likely to devote more attention to emotionally charged cases, and (iii) used not only forensic evidence in the decision making but also tactical, unverified information of the police inquiry. Interestingly, the measured contextual influences did not deviate significantly from a control group of laypeople.     

The use of the Personality Assessment Inventory (PAI) in assessing offenders

The intersection between the legal and mental health professions is sometimes marked by controversy, and the application of psychological assessments to forensic issues is no exception. However, the field of psychological assessment holds particular promise for clarifying decision making within the forensic arena, as it can bring a particularly well-established body of theory and data to bear upon clinical forensic practice. This article describes one psychometric instrument, the Personality Assessment Inventory, as an example of how particular assessment instruments can help inform this process.     

Investigation Delayed Is Justice Denied: Proposals for Expediting Forensic Examinations of Digital Evidence*

Abstract: There is an urgent need to reduce the growing backlog of forensic examinations in Digital Forensics Laboratories (DFLs). Currently, DFLs routinely create forensic duplicates and perform in‐depth forensic examinations of all submitted media. This approach is rapidly becoming untenable as more cases involve increasing quantities of digital evidence. A more efficient and effective three‐tiered strategy for performing forensic examinations will enable DFLs to produce useful results in a timely manner at different phases of an investigation, and will reduce unnecessary expenditure of resources on less serious matters. The three levels of forensic examination are described along with practical examples and suitable tools. Realizing that this is not simply a technical problem, we address the need to update training and establish thresholds in DFLs. Threshold considerations include the likelihood of missing exculpatory evidence and seriousness of the offense. We conclude with the implications of scaling forensic examinations to the investigation.     

Improving Decision Making in Forensic Child Sexual Abuse Evaluations

Mental health professionals can assist legal decision makers in cases of allegations of child sexual abuse by collecting data using forensic interviews, psychological testing, and record reviews, and by summarizing relevant findings from social science research. Significant controversy surrounds another key task performed by mental health professionals in most child sexual abuse evaluations, i.e., deciding whether or not to substantiate unconfirmed abuse allegations. The available evidence indicates that, on the whole, these substantiation decisions currently lack adequate psychometric reliability and validity: an analysis of empirical research findings leads to the conclusion that at least 24% of all of these decisions are either false positive or false negative errors. Surprisingly, a reanalysis of existing research also indicates that it may be possible to develop reliable, objective procedures to improve the consistency and quality of decision making in this domain. A preliminary, empirically-grounded procedure for making substantiation decisions is proposed.     

Decision support for using mobile Rapid DNA analysis at the crime scene

Mobile Rapid DNA technology is close to being incorporated into crime scene investigations, with the potential to identify a perpetrator within hours. However, the use of these techniques entails the risk of losing the sample and potential evidence, because the device not only consumes the inserted sample, it is also is less sensitive than traditional technologies used in forensic laboratories. Scene of Crime Officers (SoCOs) therefore will face a ‘time/success rate trade-off’ issue when making a decision to apply this technology.In this study we designed and experimentally tested a Decision Support System (DSS) for the use of Rapid DNA technologies based on Rational Decision Theory (RDT). In a vignette study, where SoCOs had to decide on the use of a Rapid DNA analysis device, participating SoCOs were assigned to either the control group (making decisions under standard conditions), the Success Rate (SR) group (making decisions with additional information on DNA success rates of traces), or the DSS group (making decisions supported by introduction to RDT, including information on DNA success rates of traces).This study provides positive evidence that a systematic approach for decision-making on using Rapid DNA analysis assists SoCOs in the decision to use the rapid device. The results demonstrated that participants using a DSS made different and more transparent decisions on the use of Rapid DNA analysis when different case characteristics were explicitly considered. In the DSS group the decision to apply Rapid DNA analysis was influenced by the factors “time pressure” and “trace characteristics” like DNA success rates. In the SR group, the decisions depended solely on the trace characteristics and in the control group the decisions did not show any systematic differences on crime type or trace characteristic.Guiding complex decisions on the use of Rapid DNA analyses with a DSS could be an important step towards the use of these devices at the crime scene.     

浅谈高坠案的现场勘查与法医学检验鉴定要点

高坠案是司法实践检案最常见的类型之一.高坠案的性质有他杀、自杀和意外,多见于后两者.但受高坠案发的突然性、现场多无人在场、很少有可靠的痕迹物证等客观条件限制,使得高坠案的性质判断极其困难.以基层司法实践检案研究为背景,从对高坠现场的坠落起点、坠落空间、水平移行距离、坠落终点进行客观仔细的勘查,全面系统的法医检验鉴定,深入详细的调查走访等多个方面进行全面的阐述和介绍.     

“CSI效应”对香港华人群体的科学证据感知评估

电视是向公众传递信息的强大媒介。最近,法庭科学和刑事司法相关题材内容在各种媒体激增,伴随着公众对法庭证据的期望提高,"CSI效应"(犯罪现场调查影视剧效应)应运而生。本研究对CSI效应的探讨有两个方面的贡献。第一,验证了在香港中国人群中是否存在CSI效应。第二,采用模拟陪审团模式,从实证角度出发全面考察CSI效应。研究发现,尽管涉及法庭科学证据的媒体报道数量确实在某种程度上影响了参与者对法庭证据的感知,但这种感知并不影响参与者对法律的判断。法庭科学题材影视剧的观众在控方仅出示法庭证据时不可能判定被告有罪,在仅出示证词时也不可能判定被告有罪。当提交法庭证据时,唯一判定被告有罪的重要预测因素是参与者对科学证据可靠性的评价。本研究的结果表明在香港不存在CSI效应。     

Proposing Problem-Based Learning for teaching future forensic speech scientists

In the last 10–15 years, Masters programmes and undergraduate modules have emerged in the UK that teach forensic speech science. Forensic speech science is the forensic subdiscipline concerned with analysing speech recordings, such as telephone calls of unknown speakers, when they arise as evidence. In order to answer questions surrounding the identity of the speakers in these recordings, forensic speech analysts draw on their expertise in phonetics and acoustics. Even though existing UK forensic speech science programmes do not claim to train students to a level where they are in a position to carry out real-life forensic casework, a proportion of the graduates from these programmes do go on to fill discipline-specific roles in security organisations or for private providers of forensic speech analysis. It is therefore surely in the community’s interests to review educational approaches to capitalise on the current training opportunities. This paper specifically proposes to explore the potential of a Problem-Based Learning (PBL) approach to forensic speech science teaching. PBL is a student-centred learning approach that heavily relies on the students’ independence in the solving of ill-structured problems. PBL has shown to be beneficial to programmes that directly lead on to discipline-specific professional roles, and has even become the standardised teaching approach in some of those areas (medicine being the flagship example). Given its reported success in other disciplines, the question arises as to whether PBL could bring similar benefits to prospective forensic speech practitioners and to forensic speech science as a whole.     

法证披露模型:应当向法证专家披露什么和法证专家应当披露什么?

法律上的披露问题主要集中在检控方向辩护方提供或者隐瞒了哪些证据。在本文中,我们将披露的概念扩展到更广泛的情境下,在这种情境下,披露失误可能导致误判。我们引入了一个概念模型,即“法证信息披露”,它涉及哪些信息应该披露给法证检验人员,以及法证检验人员应当披露哪些信息。本文全面概述了四类利益相关者的动态交互:法证服务、调查、法律和外部利益相关者。我们通过五个问题讨论了法证信息披露模式的有效实施,即如果要向法证检验人员或者由法证检验人员提供最好的信息,以提高法证决策质素,并尽量减少偏差,则什么时候进行披露?披露什么?如何披露?向谁披露?为什么披露?     

The Influence of Actuarial Risk Assessment in Clinical Judgments and Tribunal Decisions about Mentally Disordered Offenders in Maximum Security

Research has shown that actuarial assessments of violence risk are consistently more accurate than unaided judgments by clinicians, and it has been suggested that the availability of actuarial instruments will improve forensic decision making. This study examined clinical judgments and autonomous review tribunal decisions to detain forensic patients in maximum security. Variables included the availability of an actuarial risk report at the time of decision making, patient characteristics and history, and clinical presentation over the previous year. Detained and transferred patients did not differ in their actuarial risk of violent recidivism. The best predictor of tribunal decision was the senior clinician's testimony. There was also no significant association between the actuarial risk score and clinicians' opinions. Whether the actuarial report was available at the time of decision making did not alter the statistical model of either clinical judgments or tribunal decisions. Implications for the use of actuarial risk assessment in forensic decision making are discussed.     

Initial evidence for the assimilation hypothesis

The assimilation hypothesis dictates that knowledge of prior evidence makes legal decision makers assign more weight to subsequent evidence. For example, the evidentiary power of a line-up identification is perceived to be stronger if the decision maker knows that the suspect has confessed, compared to when knowledge of the confession is absent. In three studies, the assimilation hypothesis was tested. As expected, knowledge of DNA-evidence inflated the estimated strength of subsequent eyewitness identification evidence (Study 1), and also inflated overall conviction and conviction rate (Study 2). A similar assimilation effect was found with knowledge of the suspect’s dangerous psychopathology (i.e. psychopathic and anti-social personality traits). Such knowledge inflated the estimated strength of fingerprint evidence. In conclusion, the assimilation effect is a threat to rational legal decision making in both lays (Study 2) and professional judges (Studies 1 and 3).     

基于似然率方法的语音证据评价

法庭话者识别技术引入我国已有二十多年,目前该技术已经广泛应用于各类刑事和民事案件中。纵观世界各国的法庭证据评价体系,除了DNA证据以外,其他证据检验鉴定结论的表述通常有三种:同一认定、否定排除和倾向性意见。简单肯定和否定的结论存在很大的弊端,即过高估计了证据的力度,因而有时可能会造成错案。鉴于此,国外一些学者提出在鉴定结论的表述和价值评判上引入基于贝叶斯理论的"似然率"方法。本文结合目前的法庭话者鉴别方法,重点介绍基于贝叶斯理论下的"似然率"理论体系,并阐明该方法的优越性、局限性以及一些亟待解决的问题。     

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 role of DNA in criminal indictments in Israel

In their investigations of criminal cases, law enforcement agencies rely heavily on forensic evidence. Numerous studies have examined the scientific and technological advancements of DNA testing, but little evidence exists on how the availability of DNA evidence influences prosecutors' decisions to move cases forward in the criminal justice system. We created a new database by juxtaposing data from the Forensics Division of the Israel Police, which recorded the presence (or not) of DNA profiles in criminal cases (n = 9862), and data on the indictment decision for each case (2008–2019). Rates of indictments are computed for each case, and trend lines are used to present variations in the rates of indictment decisions with and without DNA profiles. Approximately 15% of all criminal cases without DNA presented to the prosecutor's office are subsequently prosecuted, compared with nearly 55% of cases with DNA profiles. The presence of DNA evidence influences the prosecutor's decision to move a case forward in the criminal justice system. Utilizing a scientific approach to prosecute offenders is a welcome development; however, DNA evidence is not infallible, and caution must be exercised in regard to DNA's overuse in the legal system.     

The value of eye-tracking technology in the analysis and interpretations of skeletal remains: A pilot study

This initial study is the first to use eye-trackers as a tool in order to study gaze pattern strategies and decision making processes involved in the assessment of skeletal remains. Three experienced participants were asked to wear eye-tracking glasses (Tobii Pro Glasses 2) when estimating sex and age-at-death of one set of skeletal remains from a known archeological sample. The study assessed participants' fixation points (the features of the skeleton focused on), fixation duration (the total time spent on each assessment and feature) as well as visit count and duration (the total number of visits and the duration of visits to particular areas). The preliminary results of this study identified differences in gaze “strategies” with regards to fixation points, visit duration, and visit counts between the participants. The data generated provide a starting point for assessing how such technologies could be used in order to more fully understand the decision making processes involved in forensic anthropological interpretations and their role in forensic reconstructions.