This work presents a background on the chemical complexity of fire debris analysis, including an ever-present matrix of pyrolysis products as the catalyst that led to the creation of the National Center for Forensic Science's Fire Debris Database. A selection of these 1,000+ casework-relevant ground truth samples was used to create two newly proposed analyst workflows to connect the current method of categorical reporting with evaluative reporting practices reflective of the strength of the evidence. Both workflows use linear sequential unmasking to help mitigate bias, a discrete scoring system for quantification of the analysis, and receiver operating characteristic (ROC) curves to bridge together categorical and probabilistic reporting by indicating the optimum decision threshold the analysts are operating from when they make a decision. Both workflows also allow a machine-learning component to be included in evaluating the evidence and are practical methods for obtaining validated performances for human and machine decisions. The second workflow includes subjective logic, which provides a means of determining the uncertainty inherent to the opinion made by the analyst and the machine learning computational model. ‘Fuzzy categories' and an opinion triangle connect the opinion offered by the analyst given their perceived uncertainty to the ROC curve so a categorical decision can be made. For each workflow, three analysts independently assessed 20 randomly chosen samples from the Fire Debris Database and followed the ASTM E1618-19 standard fire debris analysis method. The resultant area under the ROC curve for each analyst for each workflow was 0.90 or higher, indicating that all were in the very good to excellent range for diagnostic classifiers, as was the machine learning model tested in the second workflow. Recommendations for implementing a performance validation workflow, how repetitive engagement can help the individual analyst and insights on using these for performance validation and training purposes are also included.

Si les développements technologiques dans le domaine de la science forensique améliorent sans contredit les capacités de détection et la précision des appareils et des analyses effectuées, la qualité, l’intégrité, l’efficacité et l’efficience de l’exploitation des traces matérielles à des fins judiciaires et sécuritaires demeurent avant tout tributaires de décisions humaines prises tout au long du processus forensique, de la scène d’incident au tribunal. À ce sujet, bien qu’ils soient désormais reconnus comme des acteurs au premier plan du déploiement des efforts forensiques, les techniciens en identité judiciaire responsables de l’investigation des scènes d’incident n’ont fait l’objet que de très peu d’études empiriques. Pourtant, les quelques études qui sont disponibles mettent en lumière un degré élevé de variabilité dans leurs pratiques et leurs performances en matière de recherche et de collecte de traces matérielles, suggérant ainsi un processus décisionnel sur lequel nous ne savons toujours que très peu de choses. Dès lors, la thèse se propose de mieux comprendre, à travers une lentille théorique inspirée de certains concepts-clés issus de la sociologie de l’expertise et de la sociologie de la police, l’orientation des stratégies de recherche de traces matérielles par les techniciens en identité judiciaire. Plus précisément, elle cherche à approfondir les mécanismes de prise de décision et le système de savoirs occupationnels auquel se réfèrent les techniciens en identité judiciaire pour guider et justifier leurs actions, les processus de construction et d’acquisition de ces savoirs occupationnels ainsi que l’étendue du pouvoir discrétionnaire des techniciens en identité judiciaire et les conditions sous-jacentes à sa reconnaissance. Pour ce faire, la thèse repose sur une enquête de terrain de type ethnographique réalisée auprès de 19 techniciens en scène de crime du Québec entre 2020 et 2022, combinant 18 entretiens semi-directifs (35 heures) et 200 heures d’observation participante (au poste et sur de véritables scènes d’incident). Les résultats de la thèse révèlent, d’une part, que l’orientation de la recherche de traces matérielles par les techniciens en identité judiciaire est dépendante d’un système de savoirs occupationnels tacites largement ambigu, voire contradictoire par endroits, nécessitant l’interprétation des mandats, des normes informelles et des méthodes à privilégier pour prendre ou justifier une décision. D’autre part, ils suggèrent que ces savoirs seraient principalement issus, aux yeux des techniciens en identité judiciaire, de l’expérience pratique (à titre de policier et de technicien en identité judiciaire) et des échanges avec les pairs expérimentés, traduisant un discours soutenant le primat de la socialisation professionnelle informelle sur la formation et l’éducation formalisée. Enfin, les techniciens en identité profiteraient d’un important pouvoir discrétionnaire de facto leur permettant d’exercer plutôt librement leur jugement professionnel et de définir les savoirs qui sont considérés comme légitimes. Mis ensemble, ces constats proposent de comprendre la prise de décisions des techniciens en identité judiciaire en matière de recherche de traces matérielles au prisme de l’interaction entre un pouvoir discrétionnaire dynamique et un système de savoirs occupationnels ambigu et plus ou moins partagé. / While technological developments in the field of forensic science are undoubtedly improving detection capabilities and the accuracy of the equipment and analyses performed, the quality, integrity, effectiveness, and efficiency of the exploitation of material traces for judicial and security purposes remain above all dependent on human decisions made throughout the forensic process, from the crime scene to the courts. In this regard, although they are now recognized as key players in the deployment of forensic resources, crime scene examiners responsible for investigating incident scenes have only been the subject of very few empirical studies. Yet, those that are available highlight a high degree of variability in the practices and performances of crime scene examiners regarding the search for material traces, suggesting a decision-making process about which we still know very little. This thesis therefore aims to gain a better understanding of the orientation of crime scene examiners’ strategies for searching material trace through a theoretical lens inspired by key concepts of the sociology of expertise and the sociology of policing. More specifically, it seeks to investigate the decision-making mechanisms and occupational knowledge system to which crime scene examiners refer, the processes of construction and acquisition of such occupational knowledge, and the extent of crime scene examiners’ discretionary power and the conditions underlying its recognition by other stakeholders. The thesis is based on an ethnographic fieldwork among 19 Quebec crime scene examiners between 2020 and 2022, combining 18 semi-structured interviews (35 hours) and 200 hours of participant observation (at the office and at actual incident scenes). The results of the thesis reveal, on the one hand, that the orientation of the search for material traces by crime scene examiners depends on a tacit system of occupational knowledge which is largely ambiguous, even contradictory in places, leaving room for interpretation of mandates, norms, and preferred methods for making or justifying a decision. On the other hand, they suggest that such knowledge is mainly acquired, in the eyes of crime scene examiners, from practical experience (as a police officer and crime scene investigator) and exchanges with experienced peers, reflecting a discourse supporting the primacy of informal professional socialization over formalized training and education. Finally, crime scene examiners would benefit from a significant de facto discretionary power, enabling them to exercise their professional judgment rather freely and to define the knowledge that should be considered legitimate. Taken together, these findings suggest that the decision-making process of crime scene examiners in the search for material traces can be understood through the prism of the interaction between a variable discretionary power and an ambiguous, more or less shared, system of occupational knowledge.

This study sought to explore the significance of efficient murder crime scene processing. Data were collected through semi-structured interviews conducted with investigators who investigate murder cases in the Nyanga South African Police Service (SAPS) cluster in the Western Cape, to stimulate knowledge of the significance of efficient murder scene processing. A literature study relating to aspects of crime scene management and crime scene processing was conducted. From the results of this research, it appears that participants did realise the significance of efficient murder scene processing. It is, however, apparent that they experienced challenges and shortcomings with regard to efficiently processing murder scenes. Reasons for this are inexperienced investigators, overload of murder scenes to investigate, lack of human resources, and lack of cooperation between investigators and crime scene experts. The study makes recommendations that could assist the Nyanga SAPS cluster in improving the processing of murder scenes. / Police Practice / M. Tech. (Forensic Investigation)

No description available.

ABSTRACT Background: Previous criminal justice policies have been non-effective leading to overpopulated prisons and unsuccessful reintegration. There is a lack of effective supportive and/or rehabilitative services resulting in high rates of recidivism and mental health implications. Objective: This study investigated the perceived impact that incarceration and reintegration with little to no supportive and/or rehabilitative services has on the mental health status of an individual. The emphasis was on participant perception and not on professional reports because of underreporting and lack of attention to mental health in the criminal justice system. Methods: Focus groups in the Inland Empire and Coachella Valley were held to gather preliminary data used to develop the survey for this study. The survey was distributed to 88 male and female ex-offenders over the age of 18 who were no longer on probation or parole. Secondary data from United Way 211 and California State Reentry Initiative was collected to report current trends of supportive and/or rehabilitative services. Results: Incarceration was found to negatively impact perceived mental health status, but reintegration was not. Supportive and/or rehabilitative services continue to be rarely offered and accessed, but when accessed, perceived mental health status is better. Supportive and/or rehabilitative services are more readily available. People who are using these services are improving their quality of life, becoming productive members of society, and preventing recidivism. Conclusions: A paradigm shift is currently under way to reduce recidivism by improving supportive and/or rehabilitative services during incarceration and reintegration. Many offenders are receiving services as an alternative to incarceration, recidivism rates are being reduced, and ex-offenders are becoming productive members of society. The field of social work is an integral part of reentry services and should continue advocating for policies and services that support reintegration efforts at the micro and macro level.

The main purpose of this research is to assess the utilisation of the Local Criminal Record Centre (LCRC) in rape crime scenes. First responders need to attend to the crime scene and secure it as soon as possible. Other role-players such as the Family Violence, Child Protection and Sexual Offences (FCS) investigator and LCRC fieldworkers should be activated by the first responder to the rape crime scene. Ideally, role-players should be activated as soon as the case is reported to the first responder. Members of the LCRC are responsible for recording the crime scene by taking photographs, making video recordings and drawing sketch plans of the scene. The LCRC is also responsible for processing the rape scene for physical evidence such as fingerprints, blood, hair, semen and saliva. The crime scene is a major source of information as far as physical evidence is concerned. The body of the victim is also a major source of physical evidence. It is therefore essential to have the rape victim examined by a medical examiner and the crime scene to be processed by the LCRC fieldworker timeously, in order to secure physical evidence that could be used to individualise a suspect. The discovery of physical evidence could place the suspect on the scene of crime and link such suspect to the crime committed. The physical evidence could also assist in corroborating the version of events from the victim. The physical evidence could also be used to exclude suspects as well. This dissertation seeks to highlight the importance of having the LCRC processing rape crime scenes for physical evidence and to emphasise the responsibility of the first responders to activate LCRC fieldworkers to process the scene of incident timeously, in order to maximise physical evidence recovery. / Criminology and Security Science / M. Tech. (Forensic Investigation)

This study examines changes over time in 40 different Sherlock Holmes films and 39 television series and movies spanning from 1900 to 2017. Quantitative observations were mixed with a qualitative examination. Perceptions of law enforcement became more positive over time, the types of crime did not vary, and representation of race and gender improved over time with incrementally positive changes in the representation of queer, mentally ill, and physically handicapped individuals. The exact nature of these trends is discussed. Additionally, the trends of different decades are explored and compared. Sherlock Holmes is mostly used as a vehicle for storytelling rather than for the salacious crimes that he solves, making the identification of perceptions of crime in different decades difficult. The reasons for why different Sherlock Holmes projects were created in different eras and for different purposes are discussed.

Copper cable theft (CCT) has a devastating effect on the South African economy, and essential services such as TELKOM, ESKOM AND TRANSNET have been seriously disrupted, due to CCT. This dissertation focuses on the value of the cell phone record as a source of intelligence during (CCT) investigations. The cell phone industry is growing each year, and millions of people worldwide possess a cell phone. Some of these people are involved in criminal activities – which mean that cell phones, with their advanced capabilities, hold evidence which relates to crime. The activation of cell phone activity is contained on a cell phone record, and, when analysed, such information becomes intelligence which has a positive impact on CCT investigations. The purpose of this study is to assist and give guidance to investigators, in order to analyse the cell phone record(s) of CCT thieves. / Criminology and Security Science / M. Tech. (Forensic Investigation)

Copper cable theft (CCT) has a devastating effect on the South African economy, and essential services such as TELKOM, ESKOM AND TRANSNET have been seriously disrupted, due to CCT. This dissertation focuses on the value of the cell phone record as a source of intelligence during (CCT) investigations. The cell phone industry is growing each year, and millions of people worldwide possess a cell phone. Some of these people are involved in criminal activities – which mean that cell phones, with their advanced capabilities, hold evidence which relates to crime. The activation of cell phone activity is contained on a cell phone record, and, when analysed, such information becomes intelligence which has a positive impact on CCT investigations. The purpose of this study is to assist and give guidance to investigators, in order to analyse the cell phone record(s) of CCT thieves. / Criminology and Security Science / M. Tech. (Forensic Investigation)

Les sutures crâniennes ont été régulièrement étudiées au fil des siècles puisque déjà Vésale établissait une relation entre l’âge et la synostose suturale. Leur imprécision a quelque peu confiné l’observation de ces sutures dans un certain oubli, justifié en partie. Il est clair que leur fiabilité quant à l’estimation de l’âge au décès reste discutable et ce, pour diverses raisons. Leur observation est difficile et dès lors sujette à subjectivité dans l’appréciation de leurs stades de fusion. De plus, leur apparence sur le crâne sec peut être altérée par divers artéfacts de conservation (cire, vernis…). Outre l’observation des classiques sutures ectocrâniennes de voûte et l’utilisation des méthodes habituelles en la matière (méthode de Acsádi et Nemeskéri, méthode de Masset), nous avons orienté notre étude vers des sutures peu voire pas exploitées, à savoir les sutures palatines, les sutures fronto-naso-maxillaires et les sutures de l’os zygomatique. Ces trois groupes suturaux ont la particularité d’évoluer de manière très lente vers la fusion, à tel point que peu d’individus en présentent une oblitération complète. Face au vieillissement de la population et de par notre expérience médico-légale et anthropologique d’étude de pièces osseuses de personnes âgées, nous avons estimé qu’il était utile de se pencher sur des collections particulières de sujets d’âge avancé, afin d’apprécier l’évolution morphologique de ces sutures faciales. Si certaines personnes fort âgées gardent malgré tout des caractéristiques suturales peu évoluées, il existe dans l’ensemble, une progression suturale quasiment constante en fonction de l’âge. Nous avons tenté de la cerner, en attribuant à ces sutures, des degrés bien définis de cette progressive fusion et par là, l’aboutissement à un coefficient moyen d’oblitération suturale, se traduisant aisément en pourcentage d’oblitération ou pouvant être introduit dans des équations de régression. Tout en connaissant les limites de cette approche, nous pouvons estimer qu’elle peut rendre des services lors de l’étude de restes humains squelettisés, notamment s’ils appartiennent à des personnes fort âgées, dès lors qu’à ces stades de vieillissement, peu de méthodes restent encore applicables. D’autre part, l’approche en pourcentage d’oblitération suturale rend également des services lorsque les crânes étudiés sont fragmentés. C’est la situation que nous rencontrons actuellement lors de l’étude d’une très importante collection anthropologique à l’Institut royal des Sciences naturelles de Belgique. Cette observation suturale pourra également – à l’avenir – trouver un terrain d’approche fort utile par l’étude des sutures en CT-Scan ou en micro-CT. Enfin, grâce à ces techniques modernes d’imagerie médicale, les sutures trouvent un regain d’intérêt dans une application toute particulière, qui est celle de l’identification comparative, puisqu’il apparaît que le « dessin sutural » s’avère tout à fait propre à chaque individu.