It is not uncommon for an individual to commit arson as a method of concealing a crime, whether the goal be to destroy a body, DNA evidence, or any other information that may link the suspect to the scene. Fortunately, for investigators, setting a fire to the crime scene does not always destroy all evidence. Some pieces of evidence are more resilient than others. For example, evidence such as ignitable liquids and other accelerants can often be detected after the fire. In the event that an item of evidence like clothing is not completely incinerated, the presence of biological fluids may also be detected through presumptive testing and eventually lead to the identification of an individual through DNA analysis. The purpose of this study was to determine whether or not DNA analysis can be performed effectively after heated passive headspace concentration, without causing irreparable degradation to DNA evidence. Heated passive headspace concentration is a common procedure for extracting ignitable liquids from a substrate to identify and confirm the presence of that substance. This process requires long incubations at fairly high temperatures within a tightly sealed vessel to prevent evaporation. If practitioners can delay DNA analysis steps, move straight into heated passive headspace concentration, and lower the chances of losing a portion of the ignitable liquid to evaporation, it may assist in arson investigations. This study explores DNA quantity and quality in saliva and semen stains after incubation times and temperatures based on the recommended upper and lower temperature and timeframe limits of ASTM Guidelines E1412-19 and E1388-17 entitled “Standard Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by Passive Headspace Concentration with Activated Charcoal” and “Standard Practice for Static Headspace Sampling of Vapors from Fire Debris Samples,” respectively. Possible DNA analysis inhibitors such as gasoline, open flame, and burnt substrate were also explored. It was determined that while open flame in direct contact with a biological stain caused significant damage in all saliva stains and some semen stains, the presence of gasoline and burnt substrate did not appear to inhibit DNA analysis. Additionally, heated passive headspace concentration conditions did not appear to cause significant degradation or inhibition that would result in an incomplete genetic profile. Further experimentation is necessary given the presence of extraneous factors. For example, the initial amount of DNA deposited onto substrates was unknown. However, it is reasonable to state that performing heated passive headspace concentration before DNA analysis may be a feasible option if desired in a forensic laboratory.

It has been previously shown that SERS provides a rapid, confirmatory technique for the detection of blood, one of the most commonly found body fluids at a crime scene, from samples extracted with 1 µL of 50% acetic acid and placed on Au nanoparticle substrates developed by this laboratory. In recent results, the SERS spectra of blood extracted using a 50% acetic acid procedure is distinguished from 30 other reddish-brown stains (RBS) that do not contain blood, with 100% sensitivity and specificity using a partial least squares discriminant analysis (PLS-DA). A blind study was performed and 12 blinded samples were tested using the statistical method. All stains were identified as blood or non-blood with 100% accuracy. While peripheral blood and menstrual blood share many components, the complexity of menstrual blood is further enhanced by the addition of vaginal secretions. Further demonstrating SERS specificity, differential extraction procedures using water and acetic acid allow peripheral and menstrual blood to be distinguished. Given the sensitivity of SERS to identify bloodstains invisible to the naked eye, it is important to establish what limitations luminol might impose for SERS identification of bloodstains. SERS sensitivity allows blood diluted by a factor of at least 100 to be detected in the presence of undiluted luminol when using the acetic acid procedure. Current results demonstrate that the SERS detection limit is at least 103 diluted bloodstains when 1% luminol solutions, capable of producing the bright blue glow, are employed. In sexual assault cases, it may be necessary to identify the presence of semen prior to DNA analysis. Sexual assault cases may also require the identification of the presence of vaginal fluid in certain scenarios. A stain extraction method prior to SERS analysis was optimized for both semen and vaginal fluid by testing different extraction procedures with water and acetic acid. In semen, the acetic acid procedure was found to produce a signal intensity 4 times that of the water extraction procedure. Preliminary results show that for vaginal fluid, the water procedure was found to produce a SERS signal intensity more than 3 times that of the acetic acid procedure. Using differing solubilities of the chemical components of these body fluids, mixture deconvolution has been shown to be possible. The analysis of four swab types for SERS acquisition are compared in order to determine the optimal swab types for field collection of various trace body fluids. SERS analysis of trace body fluids for forensic work is a minimally destructive technique that can be applied for rapid and easy examination of evidence. The high sensitivity and specificity of SERS provides a robust spectroscopic technique for the rapid detection and identification of trace body fluids.

A review of the literature indicates that young males, who are unemployed with low levels of education, predominate in populations of pre-trial criminal offenders suspected of having a psychiatric illness, also known as “Observation Patients” according to the Criminal Procedures Act of 1977 in South Africa. Other contributory factors include a history of mental illness and non-compliance on psychiatric medication, a previous forensic history, co-morbid substance abuse and being intoxicated at the time of the offence. Dual diagnosis is considered a key contributor to criminal behaviour in this group of patients. The review of the literature also shows a significant proportion of co-morbid intellectual disability among offenders found to be psychiatrically ill at the time of the criminal event. A previous study conducted 20 years earlier, in 1986 at the Sterkfontein Forensic Psychiatric Unit by Vorster (1986) showed that the typical profile was a single, unemployed, poorly educated male in his twenties, usually with a history of psychiatric treatment. This typical profile confirmed the evidence in the literatures at the time of the study.

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Skeletal remains exposed to an outdoor context are prone to post-mortem damage and fragmentation, making skeletal analysis difficult for the anthropologist. Research on ancestry and sex from isolated fragments of the cranium is necessary to improve identification of fragmented remains. The zygoma has proven to be more durable post skeletonization than other cranial bones, making research relevant into variation within the zygoma. Whilst the shape of the zygoma has been studied in a South African population using morphological, metric and geometric morphometric techniques, these studies did not include Indian South Africans. The Indian South African population comprises 2.6% of the total population but make up a larger proportion of the population in certain areas. For example, Indian South Africans comprise 7.4% of the population in Kwa-Zulu Natal and 2.9% in Gauteng. More specifically, Indian South Africans make up to 60% of the population in the suburb of Chatsworth with a further 91% of the population in sub-area of Arena Park, and 80% of the population in the Laudium suburb of Gauteng. Therefore, Indian South Africans must be included in anthropological studies attempting ancestry classifications. The purpose of the study was to assess the shape variation and projection of the zygoma attributable to sexual dimorphism and ancestral variation among South Africans, including Indian South Africans, using a geometric morphometric approach. A sample of 400 three-dimensionally (3D) reconstructed models from head CT scans of black, coloured, white, and Indian South Africans were used with an equal sex and ancestry distribution. Eleven landmarks previously described in the literature were used for the analysis. Each landmark was used to depict the most prominent points on the outline of the zygoma. Additionally, semi-landmarks were placed along the curves of the zygoma. The landmarks and semi-landmarks were tested for observer repeatability and reliability using dispersion analysis and revealed that all landmarks were repeatable. Procrustes ANOVA revealed significant differences among the population groups and between the sexes for all population groups, except between coloured South African males and females. A pairwise post-hoc test revealed that white and Indian South Africans had the most similarities except for males, where coloured and Indian South Africans had the most similarities for landmarks. Three interlandmark distances were created to assess the zygoma’s projection. The ANOVA for the projection of the zygoma revealed significant differences for both sex and ancestry except for white South African males and females and males overall for the zygomaticomaxillary length. The zygomaticomaxillary length (ZML) is defined as the maximum distance between the landmarks zygoorbitale and zygomaxilare. No significant differences were noted for female South Africans for the Superior Zygomatic Length which, is a measure of the maximum length of the superior margin of the zygoma (between porion and zygoorbitale; PorZygool). Further analysis of the zygoma’s projection involved creating angles between the interlandmark distances. The ANOVA for the angles of projection revealed significant differences between sexes and populations, except for white and Indian South African males and females at Angle1 (Angle at the intersection of ZML and PorZygoml) and Angle3 (the angle at the intersection of PorZygool and PorZygoml) and black, coloured and Indian South African males and females at Angle2 (the angle at the intersection of ZML and PorZygool). The large amount of overlap amongst ancestry groups demonstrated substantial group similarities; however, differences were noted at the zygomaxillary, zygomaticotemporal and frontomalar sutures. Overlap was also present between males and females, but on average, males were larger than females. Differences, such as a more inferior placement of the zygoorbitale landmark were noted at the inferior margin of the orbit specifically in females. Differences were also noted at the inferior margin of the orbit across all groups. Discriminant functions were created to assess the classifying ability of the shape of the zygoma. Results revealed low accuracies for ancestry classification for the shape and projection of the zygoma. However, higher accuracies were noted for sex classification for the shape and projection of the zygoma. While results demonstrate shape variation of the zygoma, the classifying ability of the zygoma is precarious at best, and the use of the zygoma in a forensic context may not be an option. However, the differences observed can be taken into consideration during medical procedures such as zygomatic and infraorbital implants. Although landmark placements were reliable and repeatable, further analysis of the zygoma using a semi-automatic surface registration method along with different imaging techniques (MicroCT and CBCT scans) may assist in the data collection procedure and may potentially increase the accuracy of the results. Furthermore, the results of the current study highlight the need for the assessment of the effects of diet, climate, age, edentulism and symmetry on the shape of the zygoma. / Dissertation (MSc (Anatomy))--University of Pretoria, 2020. / National Research Foundation (NRF) / Anatomy / MSc (Anatomy) / Unrestricted

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Estimating the post-mortem interval is important to help identify the deceased in forensic death investigations and requires biogeographically specific knowledge of the rate of decay. Decomposition is influenced by numerous variables, including clothing, climate, and vertebrate scavenging guilds, requiring local studies. Conflicting results have been reported for clothing's effect on decomposition from various international habitats, with no data for Cape Town, South Africa, despite most local forensic cases involving single clothed decedents. Most taphonomic research uses large samples of unclothed human/animal remains to increase statistical reliability, despite this design not simulating common forensic scenarios. This study examined the effect of seasonally appropriate clothing and carrion biomass load on decomposition and scavenging in the thicketed Cape Flats Dune Strandveld, a forensically significant local habitat. Clothing was identified from forensic case files and tailored to ensure an appropriate fit, preventing unrealistic scavenger access. The decay of ten ~60 kg porcine carcasses, as proxies for human decomposition, was quantitatively examined using daily weight loss. This occurred over two consecutive summers and winters between 2018 and 2020, initially comparing clothed versus unclothed carcasses, then examining single clothed carcasses to ascertain the effect of carrion biomass load. On average, double-layer coolweather clothing notably delayed decomposition in winter, but single-layer warm-weather clothing had a comparatively negligible impact in summer. Weight loss correlated with scavenging activity by the Cape grey mongoose (Galerella pulverulenta), which displaced clothing to feed on the abdomen, more so during winter. Scavenging was hindered by the denim trousers, altering feeding patterns and causing preferential scavenging on unclothed carcasses. Single carcasses received more, longer mongoose visits and decomposed quicker than multi-carcass deployments. These results suggest that clothing delays decomposition locally by modulating the effect of seasonal weather and scavenging behaviour. Additionally, research forgoing forensic realism, with large unclothed samples deployed simultaneously, will inadvertently alter the decay rate, creating inaccurate decomposition models for postmortem interval estimation. Future studies should balance statistical robusticity and forensic realism, especially in environments where scavenging is prevalent. Single carcasses clothed in forensically realistic season-specific appropriately tailored clothing should be considered with statistical replication obtained via temporally separated repeat deployments.

Introduction: The Adverse Childhood Experiences (ACE) study demonstrated that childhood maltreatment has a profound impact on adult health, leading to psychopathology, continued victimization, risky behaviors, chronic disease, suicide, and premature death. Persons involved in the forensic mental health system are characterized by a greater degree of cumulative risk – exposed to greater and more prolonged ACEs during critical developmental periods who also face disproportionate exposure to psychosocial and economic deprivation, limited health care access, and other such factors that compound lifetime health concerns. In the current study, we seek to build upon emerging knowledge of ACEs in forensic mental health consumers by examining clusters of persons differentially exposed to ACEs in relation to a range of health and behavioral outcomes. Method: Archival data were used; participants were randomly sampled who had been admitted to the facility and released between 2005 and 2013. Of 250 possible participants identified by the facility’s Quality Management team, data were collected and coded for the resulting 180 persons. Records included admission and discharge summaries, criminal background records and associated pre-sentencing reports, and annual medical, social services, and psychiatric evaluations. Data pertaining to ACEs and characteristics of the early environment, mental and physical health, and criminality and aggression were coded for each participant. For this presentation, we examined outcomes related to adult physical health (e.g., chronic disease conditions, head injuries), mental health (e.g., suicidality, psychiatric admission history, psychiatric diagnoses), and criminogenic behavior (e.g., characteristics of arrest history, onset of aggression) using a series of logistic regression analyses, with differing ACE risk bands as ordinal predictors of our outcome variables. These include persons with an ACE score of 0-1 (40.6%, n = 73), 2-3 (27.2%, n = 49), 4-5 (16.1%, n = 29), and 6+ (16.1%, n = 29). Results & discussion: None of the outcomes for medical history were significantly different across the risk bands, potentially due to high occurrences among the sample, with over 79% reporting a chronic disease. The relationship between risk band and sexual arrest history was significant (p = .045), with those in lower risk bands more likely to be arrested for a sexual offense. This may be due to the additional planning and executive functioning required to engage in these types of crime. There was a significant relationship between risk bands and age at first arrest (p = .032), with the highest risk band arrested at younger ages. There was also a significant relationship for age at first aggression (p < .001) and age at first psychiatric hospitalization (p < .001) with highest risk bands demonstrating aggressive behaviors and being hospitalized at earlier ages. Relationships between self-harm history (p < .001), PTSD diagnosis (p < .001), and BPD diagnosis (p < .001) were significantly related to ACE risk bands. Implications and future directions will be discussed.

Mitochondrial DNA (deoxyribo nucleic acid) is typically used in forensic casework when small quantities of high molecular weight quality DNA is not expected to be present thus negating the chances of obtaining usable nuclear DNA. Typical samples that utilized mitochondrial DNA analysis are: hair, bones, teeth, ancient remains (samples or remains that are at least 100 years old) or very old samples (samples that are less than 100 but greater than 10 years old). The current method used to evaluate mitochondrial DNA is Sanger sequencing. Although robust, it is also time consuming and labor intensive, on the other hand pyrosequencing is a nonelectrophoretic, rapid, reliable, and sensitive sequencing method which can be easily automated. Therefore pyrosequencing could enable the widespread use of mitochondrial DNA in forensic casework and reduce the amount of time spent on each sample without compromising quality. The aim of this study is to evaluate the efficacy of pyrosequencing for forensic DNA applications, in particular mitochondrial DNA. Two dispensation orders, cyclic and directed, were examined to determine if there is any effect on the sequence generated. The accuracy of pyrosequencing was evaluated by sequencing samples of known sequence provided by the FBI. The sensitivity of pyrosequencing was evaluated by sequencing samples at different DNA concentrations and inputs. Experiments were conducted to determine the ability of pyrosequencing to detect mixtures and heteroplasmy. Additionally, the ability of pyrosequencing to sequence damaged/degraded DNA was evaluated using blood, semen, and saliva samples that were subjected to three different environmental conditions. A blind study will be conducted to confirm the accuracy of pyrosequencing. Finally, a comparison study will be conducted in which pyrosequencing will be compared to Sanger sequencing.

Forensic fiber examination is an important part of trace evidence analysis. Fibers may be recovered from a crime scene that could link a particular suspect to the scene. Clothing fibers are most frequently encountered but automobile carpeting fibers may also be recovered. An understanding of the frequency of occurrence and the discrimination power of different analytical techniques is needed in order to better establish the evidentiary value of automobile carpet fiber evidence. Seventy-five automobile carpet fiber samples were analyzed using a series of techniques ranging from nondestructive to destructive. These techniques included polarized light microscopy, fluorescence microscopy, microspectrophotometry, Fourier-transform infrared spectroscopy, microtomy (cross section analysis), dye extraction and liquid chromatography-mass spectrometry. Based on the information obtained from these techniques an overall discrimination of 98.02% was calculated. Only 55 of 2775 pairwise comparisons were indistinguishable. The information was subsequently entered into a searchable database for general public use.