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The analysis of colors is omnipresent in forensics. While their use for macroscopic evidence such as soil sees a large amount of research, their correct handling is more challenging when observed under a microscope. Either for hairs or textile fibers, their color (from melanin, dyes or for birefringence analysis) is crucial in being able to compare between fibers found at a crime scene. Typically, color is quantified using a color space, such as RGB, XYZ, L*a*b*, and L*u*v*. Unfortunately, color is very subjective and often difficult to quantify accurately, even using digital detectors. Finding true matches of colors has been limited by factors including illumination, optics transmission function, and in many cases the human eye. The colors produced by the birefringence of fibers under analysis using polarized light microscopy (PLM) are known to provide quick information on the fiber identification. Nonetheless, the exact determination of the accurate colors is still either subjective to the operator or the correct calibration of the software. In this thesis, calibration of the color response of a polarizing light microscope was performed using a UV-Vis broadband spectrometer to characterize its illuminant and camera. All the color images obtained with the camera were then transformed from the common RGB encoding to L*a*b* color space using MATLAB. An empirical Michel-Lévy chart was also designed using a quartz wedge in order to calibrate retardation with empirical L*a*b* color values, also as a teaching tool for the UCF undergraduate class "Forensic Microscopy", and with a qualitative comparison with common textile fibers. The discriminatory power and uncertainty of color perception of the microscope camera and of human vision were measured and will be discussed.

The ability to associate a smokeless powder, smokeless powder residue, or organic gunshot residue (OGSR) to one another may be helpful in determining the origin of a suspected sample and aid in linking a suspect to a crime scene. In this study, smokeless powders were extracted and analyzed via gas chromatography – mass spectrometry (GC-MS) and direct analysis in real time – high resolution mass spectrometry (DART-HRMS). Subsequently, group definition was performed using hierarchical cluster analysis and principal component analysis followed by internally validated classification models. Then, smokeless powder residues were generated in-lab and extracted. Resulting residue data from each instrument was classified within the respective smokeless powder model using linear discriminant analysis (LDA) with external test sets. Residue groupings and classification models were also generated. Ammunition was loaded with known smokeless powder, then fired to collect OGSR from cloth targets. The OGSR was extracted and analyzed via DART-HRMS and GC-MS, then tested against the smokeless powder and residue models to determine the association of OGSR to its intact smokeless powder as well as to lab generated residues. Reference classes for the OGSR samples in the LDA prediction were determined via flow charts for informed analyst determination of class in smokeless powder and residue models. Standards of common smokeless powder components were pyrolyzed and an expected pyrolysis products profile was created for each sample based on the intact composition. Similarity and correlation metrics including Pearson's correlation, Sørensen-Dice similarity coefficient, and Concordance correlation were evaluated in the comparison of smokeless powder to residue and residue to expected pyrolysis products. Pearson's correlation was used in the comparison of smokeless powder to OGSR and smokeless powder residue to OGSR.

Sudden unexpected death in the young (SUDY) is the unanticipated demise of individuals aged between 1 and 40 years. In South Africa, these deaths are referred for forensic investigation. The primary aim of this study was to retrospectively investigate the frequency of known risk factors in SUDY cases admitted to Salt River Mortuary in Cape Town and explore differences between males and females. There were 1 088 SUDY cases identified with 0.9% (10/1 088) missing files. Reviewed cases were n=1 078, 62.6% (675/1 078) males, and 37.4% (403/1 078) females; 83.5% (901/1 078) adults and 16.4% (177/1 078) children, accounting for 5.6% of total admissions between 1 January 2010 and 31 December 2015. Despite the predominance of males, significantly more females (61.8%) were obese (p < 0.05). At least one primary medical condition was present in 53.7% of cases, with the leading conditions being tuberculosis (11.9 % of adult males), epilepsy (11.7% of adult males; 10.3% of female children), HIV (10.7% of adult females) and asthma (11.1% of male children). In the subset of the study population where information was available, before death, 74% of individuals were reported to have experienced prodromal symptoms; 37.6% of males and 32.4% of females did not seek medical intervention following symptoms. Information regarding a family history of sudden death was known in 237/1078 cases. In 3.2% of these cases, a family history of sudden death was reported. Significantly more males than females reported the use of tobacco, alcohol, and other illicit drugs (p < 0.05). More females were unemployed (p < 0.05). Interventions based on lifestyle modification, social support, pharmacologic needs, and awareness should be targeted at individuals with the above profiles, especially those with a family history of sudden death, as they may be high-risk groups. Findings from this study contribute new and relevant local reference data for SUDY risk profiles of males and females admitted to Salt River Mortuary.