DNA mixtures are frequently encountered in forensic casework especially in cases of sexual assault. When evidence is recovered, the sample may have come from multiple contributors in different proportions. The first part of this study examines the fidelity of contributor proportions by using the residual to analyze known mixture samples. The coefficient of determination between the expected and observed proportions was also determined and used to assess the fidelity of mixture proportions. The second part of this study involved separating major and minor contributors in a mixture by characterizing the observed proportions. Results for the 2-person mixture show that as the mass of amplified DNA decreases, the number of allele dropouts increases. Furthermore, as mass decreases, the level of variation between the expected and observed proportions increases, as determined by the residuals and the coefficients of determination. In addition, as mixture proportions become more disparate the amount of variations between the expected and observed proportions are not as great as the mass. For the 3-person mixtures, as mass decreases, the residuals increase. Also, when the coefficient of determination of the 3-person mixtures were compared to those obtained with the 2-person mixtures, it was determined that the R2 were larger for the former. This was a result of higher total amplification masses. In mixture 1:2/2:1, major and minor proportions are not distinguishable In mixture 1:4/4:1, major and minor proportions can be distinguished at 1 ng. In mixture 1:9/9:1, proportions are distinguishable at 1, and 0.5 ng. Mixtures could not be distinguished at the 0.25 ng level, despite proportion and is the result of the increase in variation with decreasing mass.

Various traumatic events such as automobile accidents, structure fires, or terrorist attacks result in traumatic and thermal injury. Fire is a destructive force that can alter or destroy evidence, and thermal alterations have negative effects on forensic and anthropological recovery and analysis. Blunt force trauma is particularly difficult to analyze because of the multiple ways in which this trauma appears on a body and the variety of objects that can impact and fracture a bone or the variety of ways a body can impact a blunt surface. As fire is a common way to cover up a crime and blunt force trauma is used as a means to kill or injure an individual, it is necessary to understand the differences between these two types of fractures that can present together on bone. The present study was performed to determine the amount of survivability of traumatic fracture patterns in remains that have been exposed to a burning event. The sample used for this investigation was composed of twenty limbs (forty long bones) from five full-grown, domestic, female sheep (Ovis aries) obtained from a farm in Connecticut. Thirty specimens were traumatized with the head of an Estwing ball peen hammer and ten were left as controls. After specimens were subjected to blunt force trauma, each was radiographed using Computed Tomography. They were then placed in a small structure, 8' x 8', that was constructed to simulate the conditions of a house fire. Each post-burn bone was analyzed based on a number of characteristics. A trauma score of "1" no trauma, "2" ambiguous, and "3" traumatic fractures were given based on these observations. CT scans were examined after bone samples had been analyzed. Again, each specimen's CT scan was given a trauma score ("1" no trauma, "2" ambiguous, and "3" traumatic fractures). Results from the bone analysis on the 30 traumatized and burned specimens revealed that 15 did not have trauma, 2 were ambiguous (i.e., they may have trauma but traumatic characteristics were not distinct), and 13 presented with distinguishable traumatic injury. Comminuted was the most prominent type of fracture, and the next most common fracture was oblique. The majority of traumatic injury was found on the middle portion of the bone. CT examination showed that 12 specimens had suffered traumatic injury. The two analyses were compared and showed an agreement of 83.3% between the trauma scores. Results show that differentiation of traumatic and thermally induced fractures is possible using various fracture characteristics as well as taphonomic indicators to determine the sequence of events.

Introduction: Care professionals suffering with poor wellbeing is a phenomenon that has been found to have a damaging effect upon individual employees, service users and organisations. Employees working in forensic settings are believed to be at increased risk of damaged wellbeing due to the unique demands of their working environment, including exposure to violence and aggression. This issue was addressed in two ways. Firstly, a systematic review of the literature on the effectiveness of person-centred interventions to improve the wellbeing of forensic professionals was prepared. Following this, an empirical study was completed which examined the ability of demands related to violence and aggression, and resources of two types (cognitive and contextual behavioural) to predict the wellbeing of employees in a high secure forensic mental health (FMH) hospital. Method: For the systematic review, relevant databases were systematically searched and 7 papers that met the inclusion criteria were identified. The included studies were quality assessed to identify strengths and weaknesses. For the empirical study, 142 employees at a high secure FMH hospital completed self-report questionnaires which examined their wellbeing, perceptions of the prevalence of aggression, beliefs about safety, attitudes towards aggression, and psychological flexibility. Results: The reviewed studies included psychological, educational and mixed type interventions. Evidence for the effectiveness of interventions was mixed, and problems with methodological quality common. The results of the empirical paper suggested that exposure to violence and aggression was not a good predictor of wellbeing. However, the beliefs staff held about safety and staff‘s level of psychological flexibility were predictive of wellbeing. Conclusions: The review concluded that the existing evidence for the effectiveness of person-centred wellbeing interventions for forensic professionals was generally of poor quality, and inadequate to provide firm recommendations. Further research to assess the effectiveness of interventions and the underlying mechanisms of wellbeing change in forensic settings was advised. The empirical paper concluded that job demands related to staff‘s cognitive appraisal of safety, and the contextual behavioural resource, psychological flexibility, were predictive of staff wellbeing. It was recommended that future interventions to improve the wellbeing of forensic professionals consider the psychological processes staff encounter in the workplace, with a particular focus on contextual behavioural resources, which have an existing evidence base in broader occupational fields. Further research using contextual behavioural interventions within forensic settings is recommended in order to develop the limited research on forensic professionals‘ workplace wellbeing.

In homicide cases, suitcases provide concealment and ease of transport of a body and reduce the likelihood of detection. When estimating a minimum postmortem interval (mPMI), it is necessary to understand the taphonomic processes that occur when a body is concealed within a suitcase. In this study, the experimental carcasses consisted of pig (Sus scrofa Linnaeus) heads concealed within either hard shell or fabric suitcases whereas control pig heads were decomposed naturally. All control pigs heads attracted blowflies (Calliphoridae) immediately and mummified within days, whereas the experimental pigs heads had an oviposition delay of approximately 72 hours and decomposed resulting in skeletonization. Differences in the arthropod species present varied between the experimental and control pigs heads. Temperature comparisons revealed significant (p <0.001) differences between the experimental and control pigs heads. How a corpse decomposes when a suitcase is used for body disposal must be considered when estimating the mPMI.

From the entomological evidence occurring on and around a corpse it is possible to determine an estimated post-mortem interval (PMI). The critical step in this examination is the accurate identification of specimens collected ensuring the application of appropriate species-specific developmental data. Current molecular techniques in the identification of forensically important Calliphoridae species from the Australian region have been explored and found to be a highly significant and valuable area of research. The cytochrome oxidase genes in the mitochondrial genome have been shown to have sufficient sequence diversity to distinguish forensically relevant Calliphoridae species. In order to target the observed sequence diversity within relevant regions of the nuclear or mitochondrial genomes, sequence specific primer (SSP) pairs are used to target polymorphisms, resulting in the amplification of specific species. This technique has proven to be both a rapid and successful identification tool in the analysis of insect taxa, especially Culicidae. SSP typing is particularly useful, as it requires no subsequent sequencing or restriction with enzymes, both of which require additional time and reagents. The aim of this research was to develop a multiplex SSP reaction for the identification of forensically important Calliphoridae species. Seven SSP pairs preliminarily designed by Harvey (2006) were utilised in the identification of Calliphora dubia, Calliphora albifrontalis, Chrysomya rufifacies, Chrysomya megacephala and Lucilia sericata. Once optimised the SSP pairs were developed into two multiplex PCR reactions. This thesis presents the experiments performed, analysis conducted and results obtained through the development of the multiplex SSP-PCR system. Initial testing of the seven preliminarily designed SSP pairs conveyed non-concordance between expected and observed results. Additional species were continually amplified, even after extensive optimisation attempts, including alternations to annealing temperature, MgCl2 and primer concentration. Of the 7 SSP pairs, 6 were re-designed to improve specificity, whilst one was removed from further testing and replaced with 2 newly designed primer pairs. 15 Continual testing of 8 SSP pairs was conducted, but only 6 could be successfully optimised. Optimisation was limited to alterations to annealing temperature, to allow for potential multiplexing. To confirm the regions and species amplified, sequencing of the PCR products was performed. Though only partial sequences were obtained for most samples the alignment shows the expected region amplified with specific species variations. Using the remaining 6 SSP pairs all species tested were identifiable, allowing for multiplexing potential to be tested. Multiplex PCR is a cost effective and efficient technique that is becoming increasing popular within a wide range of scientific disciplines. To date there has been no recorded use of this technique in relation to either forensic entomology or the analysis of forensically important Calliphoridae species. The 6 SSP pairs were manipulated to produce one successful multiplex PCR system using 3 SSP pairs to identify L. sericata, Ch. rufifacies and Ch. megacephala, and one unsuccessful multiplex PCR that amplified a single SSP pair for the identification of C. dubia and Ch. rufifacies. When both reactions are utilised, it is possible to identify all 5 forensically important Calliphoridae species tested.

For thesis abstract select View Thesis Title, Contents and Abstract

For thesis abstract select View Thesis Title, Contents and Abstract

Under an adversarial legal system, witnesses� testimony may be challenged by the opposing lawyer during cross-examination. Cross-examination has been shown to negatively affect the accuracy of children�s event reports, but as yet, the mechanisms driving this effect are unknown. Experiment 1 aimed to tease apart the roles of question type and repeated interviewing in mediating children�s cross-examination performance. Five- and 6-year-olds (N = 82) and 9- and 10-year-olds (N = 103) took part in a staged event, and 1 to 2 days later they took part in a direct examination interview. Next, either 1 to 3 days or 6 months later, all children were interviewed for a second time. For half of the children, this second interview was a repeat of their direct examination interview. The remaining children were interviewed in a cross-examination format. A second interview reduced response accuracy after both short and long delays, however, cross-examination questioning impaired the accuracy of children�s reports the most. Although, overall, children have considerable difficulty answering cross-examination questions correctly, variation in their performance has been observed. Experiment 2 assessed whether individual differences in cognitive abilities mediate cross-examination performance. Five- and 6-year-olds (N = 116) and 9- and 10-year-olds (N = 58) visited the police station and subsequently reported their experiences in direct examination and cross-examination interviews. Children�s memory, receptive language ability, expressive language ability, and intelligence were also measured. Age, intelligence, and memory predicted aspects of cross-examination performance. Overall, these cognitive factors accounted for between 16.6% and 19.5% of the variance in cross-examination outcome measures. Given the negative effect of cross-examination on children�s responding, and our inability to identify the children who are most at risk of poor performance during this interview, Experiment 3 assessed our ability to facilitate children�s responding to cross-examination questioning. Specifically, the effect of manipulating the timing of a pre-trial intervention, which gives children practice and feedback at cross-examination questioning, was investigated. Five- and 6-year-olds (N = 88) and 9- and 10-year-olds (N = 108) visited the police station. One to 3 days later they completed the direct examination interview and 6 months after the event, children were cross-examined. The timing of the preparation intervention was varied (1-day, 1-week, 1-month before cross-examination), and the children�s subsequent cross-examination performance was compared to that of children in the control group. When the preparation intervention was delivered 1 day or 1 week before the cross-examination interview, children�s cross-examination performance was significantly improved. The findings from the three experiments suggest that cross-examination is likely to pose considerable problems for children, especially younger children. Our greater understanding of factors that influence children�s responding to cross-examination questioning may guide reform of the cross-examination process for child witnesses. Bottom-up initiatives, such as pre-trial preparation, and top-down changes, including educating professionals, expert testimony, and reducing the delay to cross-examination, may improve the reliability of child witnesses� testimony during cross-examination.

The ability to successfully distinguish truthful and deceptive messages within forensic contexts is important to preserve the integrity of the legal system. Research has shown that confession evidence is highly persuasive at a trial level and that false confessions leading to wrongful convictions are problematic within the judicial system. Some recent research also suggests that that neither lay observers nor law enforcement professionals are able to successfully distinguish truths and lies in the context of confessions. Therefore, the present safeguards in the judicial system may be inadequate to detect a false confession and prevent subsequent wrongful convictions. The research presented in this thesis was designed to explore the effectiveness of methods of detecting deception within forensically relevant contexts, specifically confessions. Study One examined the impact of presentation modality and the effectiveness of indirect deception measures on credibility assessments of autobiographical accounts depicting truthful and deceptive confessions. The outcome of this study revealed that fact finders were unable to accurately classify truthful and deceptive confessions across presentation modalities and that indirect measures were unsuccessful in this context. In light of these findings, subsequent studies examined the validity of statement content analysis to discern truth from deception within the context of confessions. Study Two assessed evaluations of Criteria-based Content Analysis and the Aberdeen Report Judgment Scales, as applied by untrained observers to discriminate truthful and deceptive confessions. Findings revealed null effects and demonstrated that training in the application of content-based evaluations is an integral element of the valid application of such measures to detecting deception. Studies Three, Four and Five, therefore incorporated a comprehensive training program and focused on the application of a theoretically based method for detecting deception, the Aberdeen Report Judgement Scales, to the analysis of forensically relevant statements describing confessions, alibis and victimisation accounts. Overall, findings revealed some modest evidence for the application of this framework within deceptive contexts, however, account differences as a function of truth status were often rather small and assessments on many dimensions produced null findings. These results are discussed in terms of theoretical and practical implications for discerning truths and lies within forensic contexts.

The advent of nuclear DNA (nuDNA) analysis altered the way forensic biology was both practised and viewed by the forensic biologists, police, the legal system and the general public. The ability of nuDNA to individualise analysis of evidence and attach a statistical frequency ratio to the result, created an expectation that numerical objectivity should be part of all forensic analysis. There are few scientists who would disagree with both the need and desirability of objective measures of their results. Forensic hair examiners are no exception as indicated by numerous scientific publications specifically discussing means of objectively assessing hair and its characteristics. While mitochondrial DNA offers a partially objective measure of hair the result is destructive of the sample. A method that objectively supports the hair analysts' microscopic findings and is non destructive would be beneficial to forensic hair examination. This project attempted to develop an objective measure of hair analysis by using both traditional light microscopic comparative techniques combined with a high end digital imaging and image analysis capacity. Where objectivity equals an empirical set of numbers that can be manipulated for statistical significance, the comparative biological sciences such as histology, anthropology and forensic hair examination struggle. Forensic hair examiners have long acknowledged the difficulty, even inability, of assigning numerical values to the features that characterise one hair as being different from another. The human scalp hair is a "morphological" unit that is not readily split into component parts or even that these parts lend themselves to a number value. There have been at least nine separate studies which favourably compare the specificity of microscopic hair examinations. The challenge this study addressed was to appraise the use of numerical features in forensic hair examination, with particular emphasis on those features currently resisting numerical evaluation; specifically, colour and pigmentary characteristics. The techniques used were based on obtaining high quality digital images, and using the pixels inherent in the images to obtain numerical values of such features as colour and pigmentation. The project sample was taken from the telogen scalp hairs obtained from the hairbrushes of ten nominally brown haired Caucasians, both male and female. The focus was twofold: o Compare colour analysis of hair images from brown haired Caucasians within three standard, internationally recognized colour models, namely Red-Green-Blue (RGB) colour model; CIE XYZ Tristimulus (1931) colour model; and CIE L*a*b* (1976) colour model. o Using the same sets of digital images, undertake pattern recognition analysis both intra and inter individual hair samples. Discriminate analysis of the mean colour values collected for each of the inherent colour variables in the three colour models (red, green, blue; X, Y, Z and L*, a*, b*) indicated the RGB colour model gave the least separation of brown haired individuals; CIE XYZ and CIE L*a*b* separated several individuals for all their individual samples and several other individuals were mostly separated with only one of their own samples overlapping with another. Pattern analysis used a small area that represented the overall pigment patterning observed along the length of the hair shaft. This area was extracted from the digital image within V++ Digital Optics image analysis software. The extracted pattern piece was then compared with other sample images within the same hair and four other hairs from the same individual. Pattern extracts were also compared between person hair samples. The comparisons generated a set of numerical values based on the pixel number on the "x" axis of the whole image and the average difference between the extracted pattern image and the whole image. Analysis of this data resulted in log distributions when persons were matched with themselves. It was also possible to refer an unknown pattern extract to this distribution and based on probabilities, predict as to whether or not the unknown sample fell within any of the known sample's distribution.