Helping formulate propositions in forensic DNA analysis

The Bayesian paradigm is the preferred approach to evidence interpretation. It requires the evaluation of the probability of the evidence under at least two propositions. The value of the findings (i.e., our LR) will depend on these propositions and the case information, so it is crucial to identify which propositions are useful for the case at hand. Previously, a number of principles have been advanced and largely accepted for the evaluation of evidence. In the evaluation of traces involving DNA mixtures there may be more than two propositions possible. We apply these principles to some exemplar situations. We also show that in some cases, when there are no clear propositions or no defendant, a forensic scientist may be able to generate explanations to account for observations. In that case, the scientist plays a role of investigator, rather than evaluator. We believe that it is helpful for the scientist to distinguish those two roles.     

The effect of tape type,taping method and tape storage temperature on the retrieval rate of fibres from various surfaces: An example of data generation and analysis to facilitate trace evidence recovery validation and optimisation

This paper aspires to assist those tasked with data generation and analysis for the purpose of the validation and/or optimisation of trace evidence recovery. It does so via a detailed report of the authors’ approach to this problem in the context of target fibre retrieval using self-adhesive tapes.Textile fibres can provide valuable evidence at both source and activity levels. This ability stems from their near ubiquity in the man-made environment, their potential for high levels of discrimination (especially when found in combination) and their reproducible transfer and persistence behaviours. To realise this value for the criminal justice system, it is vital that police forces and forensic providers are collectively able to search for, recover and analyse fibres found at crime scenes and correctly evaluate their evidential value.ISO accreditation provides quality assurance for such activities. The work reported in this paper was part of a study to validate crime scene fibre retrieval processes for the purposes of ISO17020 accreditation. However, it is hoped that it will be of assistance to those wishing to validate and/or optimise forensic fibre recovery whether at the crime scene or in the laboratory. Further, the methods described may be of value to those who need to validate and/or optimise the recovery of other types of trace evidence.This paper outlines a series of experiments that investigated the effect of four factors on the rate at which target fibres could be recovered from surfaces by tape lifting. The factors were tape type (with two levels, namely: J-LAR and Crystal Tabs), tape storage temperature (three levels: −5 °C, room temperature [19 ± 1 °C] and 35 °C), taping method (two levels: zonal and one-to-one) and surface (12 levels: each being a surface type commonly encountered at crime scenes). This resulted in 144 unique experimental conditions. For each of these, five repeat fibre recovery rate determinations were carried out, generating 720 data points. All surfaces were clean and dry prior to target fibres being transferred and recovered. In all cases, the tapes were applied to the surfaces at 19 ± 1 °C.These experiments showed that the surfaces can be divided into three stable clusters based on the median and interquartile range of the fibre retrieval rate achieved from each of them. Also, they showed that, in terms of the proportion of the target fibres retrieved, typically and setting aside interaction effects:

• •Crystal Tabs outperformed J-LAR;
• •rolls of tape stored at −5 °C and 35 °C outperformed those stored at room temperature;
• •one-to-one taping outperformed zonal taping.

However, notably, a good degree of between-condition overlap was also apparent in the data. To understand this, a four-way factorial ANOVA model was built which revealed significant and substantive effects for all four main effects and for 10 of the 11 interactions. Importantly, the four-way interaction term was amongst those found to be significant. The interplay between the effects of the four factors was analysed by means of simple effects tests and pairwise contrasts. Tables and interactive parallel coordinate plots have been created. Using these it can easily be seen which of any given pair of levels of each of the four factors resulted in the higher fibre retrieval rate under any one of the unique conditions of the study, and the effect size and statistical significance of this observation.Qualitative evaluations of the effect of tape storage temperatures on tape pliability and its propensity to tear in use were also made.     

Does procedural fairness matter for drug abusers to stop illicit drug use? Testing the applicability of the process-based model in a Chinese context

ABSTRACT

This study examined the influences of procedural fairness on Chinese drug users’ efforts to stop substance abuse, with a primary goal to test the applicability of the process-based model in the Chinese context. According to Tyler (1990 Tyler, T. (1990). Why people obey the law. New Haven, CT: Yale University Press. [Google Scholar], Why people obey the law. New Haven, CT: Yale University Press), the core theoretical argument underpinning the process-based model is that if citizens consider the police to be fair in using their powers, they will view the police as legitimate and accordingly cooperate with the police and comply with the law. Using data from a sample of 202 Chinese drug users, this study found that procedural fairness has an indirect effect on drug users’ efforts to stop illicit drug use. Specifically, procedural fairness used by the police increased Chinese drug users’ efforts to stop substance abuse through its prior effects on drug users’ perceptions of police trustworthiness. These findings provide some support for the key arguments of the process-based model of regulation, and have important implications for the direction of efforts to encourage desistance-related behavior among substance abusers.     

‘Don’t Blow Your Cool’: Provocation,Violent Coping,and the Conditioning Effects of Self-Control

Objectives

General Strain Theory (Agnew in Criminology 30:47–87, 1992) has received broad empirical support, but little is known about moderators of the strain-delinquency relationship. This study tests whether self-control attenuates the relationship between a certain type of delinquency—violence—and its most important precursor, considered a type of strain: interpersonal provocation. This study compares the conditioning effects of risk-affinity and self-control/impulsivity on the provocation-violence link, since recent work suggests differentiating between both characteristics.

Methods

The provocation-violence link is examined (1) using a scenario design with randomly varied degrees of objective provocation and a measure of projected violence, and (2) with measures of self-reported past violence and subjective sensitivity to provocation. The analyses are based on a large sample of seventh-graders (n = 2635) from five cities in Western Germany, interviewed in 2013. Linear probability models regressing violence measures on personal traits, provocation measures, and their interactions are estimated.

Results

Both self-control and risk-affinity moderate the relationship between subjective sensitivity to provocation and past violent behavior. Students with high self-control are able to control their anger and do not turn violent, even when they feel provoked easily. However, only risk-affinity significantly amplifies the effect of objective provocation on prospective violence when simultaneously controlling for the conditioning effect of self-control.

Conclusions

Findings underscore that both self-control and risk-aversion are important coping resources. This study highlights the importance of using internally consistent and mechanism-congruent measures in the study of illicit coping processes and conditioning factors and discourages from using composite, potentially multidimensional measures.

     

Characterisation and discrimination of so-called metallised fibres found in clothing and decorative materials originating from the consumer market

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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.     

Low Resting Heart Rate and Rational Choice: Integrating Biological Correlates of Crime in Criminological Theories

Purpose

The current work examined the association between low resting heart rate and perceptions of the costs and benefits of criminal behavior.

Methods

Data were gathered from a sample of students in introductory criminal justice classes. Perceptions of the costs and benefits of crime were measured in response to scenarios describing assault, theft and drunk driving.

Results

Those with low resting heart rate perceived a lower likelihood of sanction and were less likely to anticipate a sense of guilt/shame should they commit assault during a confrontation. Those with low resting heart rate were also more likely to indicate that they would commit the act described in the assault scenario. Anticipated guilt/shame mediated the relationship between low resting heart rate and intent to engage in assault.

Conclusions

Low resting heart rate was related to estimations of the costs and benefits of offending. Perceived costs (anticipated guilt/shame) mediated the relationship between resting heart rate and intent to commit assault.     

Recommended Films

First Run Features, The Film Center Building, 630 Ninth Avenue, Suite 1213, New York, NY, 10036. Website: https://www.firstrunfeatures.com/

Patrimonio (Directors: Lisa F. Jackson and Sarah Teale, 2018)     

Movie review essay

While Paul McCold’s intent to clarify the compatibility of restorative justice and community justice conceptual frameworks is laudable, his effort provides as much confusion as clarity (McCold, 2004 McCold, P. (2004). Paradigm muddle: The threat to restorative justice posed by its merger with community justice. Contemporary Justice Review, 7: 13–35. [Taylor &; Francis Online] , [Google Scholar], this issue). This piece identifies some of the conflicts inherent in the roots of the development and growth of restorative justice. It also raises concerns regarding how restorative justice theoreticians and practitioners consider community, the role of strangers, empowerment, prevention, and punishment within restorative frameworks. The authors of this piece conclude that, while it remains important to safeguard the underlying principles of restorative justice, it is also necessary to remain open to new possibilities and to new ideas.     

Letter to the editor: Commentary on “Strategic choice in linear sequential unmasking,Roger Koppl,Science & Justice,https://doi.org/10.1016/j.scijus.2018.10.010”

This letter to the Editor comments on the paper ‘Strategic choice in linear sequential unmasking’ by Roger Koppl (Science & Justice, https://doi.org/10.1016/j.scijus.2018.10.010).     

Witness Interview Training: a Field Evaluation

The effect of a witness interviewing training program on interviewing performance in actual investigations was examined. Eighty interviews, conducted by police officers in one Canadian organization, were coded for the presence of 38 desirable practices. Results showed that, in general, trained interviewers outperformed their untrained counterparts. Specifically, there was a large improvement in engage and explain behaviors (d = 1.65), a moderate improvement in account behaviors (d = 0.54), and a large improvement in closure behaviors (d = 0.90). Trained interviewers also used more open-ended questions and fewer leading questions. The implications of the findings for transferring interviewing skills from the classroom to the field are discussed.     

Recommended Films

Roadside Attractions, 7920 Sunset Blvd., #402, Los Angeles, CA 90046. Website: https://www.firstrunfeatures.com/

Marianne and Leonard: Words of Love (Director: Nick Broomfield, 2019)     

Naturally Occurring Social Support in Interventions for Former Prisoners with Substance Use Disorders: Conceptual Framework and Program Model

Purpose

Naturally-occurring social support is underutilized in interventions with former prisoners with substance use disorders. This paper proposes a conceptual framework followed by a program model to inform the development of naturally-occurring social support interventions with former prisoners with substance use disorders.

Methods

We reviewed all published social support interventions designed for former prisoners and people with substance use disorders over a ten year period. Building on the implications of this review, empirical literature, professional experience, and theory, we propose a conceptual framework for naturally-occurring social support programs.

Results

Few published programs exist that actively incorporate social support providers into the program model. Of these, even fewer use naturally-occurring support. Expanding on gaps in theory and program approaches, the conceptual model posits that it is the appropriate match of support needs and provision that reinforces emotions, cognitions, and behaviors, that in turn, promote adaptive outcomes.

Conclusions

With mounting pressure to identify interventions that will reduce high re-incarceration rates, this paper draws attention to a neglected, potentially effective, and low cost resource - naturally-occurring social support. The described program, Support Matters, illustrates how social support interventions can be used with former prisoners to promote reduced relapse to substance misuse and crime.     

DNA-based identification of big cats and traditional Chinese medicine artifacts in the Czech Republic

The aim of this study is to provide an overview of ongoing research on and the development of identification tools for big cats (Panthera tigris, Panthera leo, Panthera pardus, …). The set of tools includes a species-specific RTPCR quantitation system (nuclear and mitochondrial), STR multiplexes, a rapid system for big cat species determination, and a database solution.     

A review of experimental design in forensic taphonomy: moving towards forensic realism

Forensic taphonomy as a discipline requires standardization to satisfy Daubert criteria for scientific data to be admissible in court. In response, there has been a shift towards quantification of methodology and estimating the postmortem interval. Despite these advances, there are still biases and limitations within the discipline not explicitly addressed in the early stages of experimental design nor in final published works. In this article, unresolved debates with respect to the conductance and reporting of forensic taphonomic research are reviewed, beginning with the nature of experimental cadavers, human or animal analogues and their body size, and second, the forensic realism of experimental setups, specifically with respect to caging, clothing and number of carcases. Pigs, albeit imperfect, are a good model to gain a general idea of the trends that may be seen in humans in subsequent validation studies in facilities where human donors are available. To date, there is no consensus among taphonomists on the extent of the effect that body mass has on decomposition progression. More research is required with both human cadavers and non-human analogues that builds on our current knowledge of forensic taphonomy to answer these nagging questions. This will enable the discipline to make the reliable assumption that pigs and donor decomposition data can be applied to homicide cases. A suite of experimental design aspects is suggested to ensure systematic and standardized data collection across different biogeoclimatic circumstances to identify and quantify the effects of potential confounding variables. Such studies in multiple, varied biogeographic circumstances with standardized protocols, equipment and carrion will facilitate independent global validation of patterns. These factors are reviewed to show the need for adjustments in experimental design to ensure relevance and applicability of data within locally realistic forensic situations. The initiation of a global decomposition data network for forensic taphonomists is recommended.

Key points

• Pigs are a valuable, albeit imperfect, proxy for human decomposition studies.
• There are few or conflicting data on effects of carcase size, carrion ecology, exclusion cages and scavengers.
• We recommend single, clothed, uncaged carcases for baseline research to reflect regionally specific forensic casework.