Fatal accidents on the road are an unfortunate daily occurrence, with almost 30,000 deaths resulting from hit-and-runs in the USA between 2006 and 2021. The identification of the driver responsible for this road crime can become a challenge. Nonetheless, the accident scene provides a large amount of trace evidence that can prove critical to this matter, one of them being the tire marks. While traditional tire mark analysis is full of physical information helping the reconstruction of the event, additional information can be extracted from the rubber left during the braking event. Each tire model is manufactured with a specific design, obtained by a chemical formulation that can become its signature. Supplemental to the molecular profile of the rubber itself, analysis of the trace and contaminant elements can help build the chemical signature for the tire rubber. This work consists of establishing the link between the tire and the skid mark and particles it left during a braking event. The difference between tire models was proved from the elemental analysis of the tire rubber itself, showing that the specific content of minor and trace elements is specific to the model. Expanding to the problem of tire marks, the first challenge consists in efficiently sampling the rubber from the road. The development of an effective procedure to lift the tire particles from the mark is demonstrated in this work. This does present some challenges, including removal of other particles present within the lift and extraction of the tire rubber for further analysis by ICP-MS, providing an elemental profile for the sampled skid mark. Finally, with the skid mark rubber analyzed, it is compared with the elemental profile of the rubber from the source tire. The results of this comparison will be discussed in both simulated (with a lab- made tire mark maker) and field cases (from braking tests performed by the Florida Highway Patrol (FHP)). The results of my research provide the forensic community with the first evaluation of elemental analysis of tire rubber to use this seldom used trace evidence, all along the analytical process, from sampling to analysis to attribution.

Current fire debris analysis procedure involves using the chromatographic patterns of total ion chromatograms, extracted ion chromatograms, and target compound analysis to identify an ignitable liquid according to the American Society for Testing and Materials (ASTM) E 1618 standard method. Classifying the ignitable liquid is accomplished by a visual comparison of chromatographic data obtained from any extracted ignitable liquid residue in the debris to the chromatograms of ignitable liquids in a database, i.e. by visual pattern recognition. Pattern recognition proves time consuming and introduces potential for human error. One particularly difficult aspect of fire debris analysis is recognizing an ignitable liquid residue when the intensity of its chromatographic pattern is extremely low or masked by pyrolysis products. In this research, a unique approach to fire debris analysis was applied by utilizing the samples' total ion spectrum (TIS) to identify an ignitable liquid, if present. The TIS, created by summing the intensity of each ion across all elution times in a gas chromatography-mass spectrometry (GC-MS) dataset retains sufficient information content for the identification of complex mixtures . Computer assisted spectral comparison was then performed on the samples' TIS by target factor analysis (TFA). This approach allowed rapid automated searching against a library of ignitable liquid summed ion spectra. Receiver operating characteristic (ROC) curves measured how well TFA identified ignitable liquids in the database that were of the same ASTM classification as the ignitable liquid in fire debris samples, as depicted in their corresponding area under the ROC curve. This study incorporated statistical analysis to aid in classification of an ignitable liquid, therefore alleviating interpretive error inherent in visual pattern recognition. This method could allow an analyst to declare an ignitable liquid present when utilization of visual pattern recognition alone is not sufficient.

Fiber analysis using birefringence has been around for years but has only recently been looked at more closely under a microscope. Recent scientists have proposed methods to correct issues found with fiber analysis using birefringence, yet there has not be a defined perfect method. This research will focus on correcting previously found issues with works by Michel-Lévy and Sorensen's, as well as other scientists involved and perfecting the analysis of fiber through birefringence. The goal will be to take this research one step further into the analysis of textile fibers by RGB value analysis and birefringence. The RGB values will be analyzed in a color analysis program to compare HEX values. The cross section of the fiber will be done to receive an accurate diameter measurement of the fiber. Those RGB values and cross section diameter will then be matched to the Michel-Lévy chart and the birefringence will be determined.

No description available.

No description available.

No / The Raman and electron impact mass spectra of synthetic indigo and its four 6,6'-dihalogeno analogues are reported and discussed. The influence of varying the halogen on these Raman spectra is considered. Particular emphasis is laid on distinguishing indigo from 6,6'-dibromoindigo and differentiating between the dihalogenocompounds, so as to develop protocols for determining whether artefacts are coloured with dyes of marine or terrestrial origin and whether such artefacts are dyed with genuine Tyrian Purple or with dihalogenoindigo substitutes that do not contain bromine. The value of even low resolution electron impact mass spectrometry in a forensic context as a means of identifying authentic 6,6'-dibromoindigo and distinguishing it from its dihalogenoanalogues is emphasised.

Television shows, in particular CSI: Crime Scene Investigation, have captured the attention of the majority of Americans. As a consequence of these shows, the "CSI effect" has evolved. The CSI effect primarily occurs when people watch crime or law related shows resulting in them gaining an unrealistic expectation of what they think should occur in real trials. This is a concern for prospective jurors who take part in criminal trials. This thesis will reveal how the CSI effect has swept the nation. A large part of this study will be devoted to illustrating how the CSI effect has had an impact on jurors, criminals and the American court system. This thesis will shed light on how television has the power to alter a juror's mind, even if it is a decision that could completely change the defendant's life. This thesis will also examine how legal professionals have strategically begun to mention the CSI effect during their trials in court. Nowadays, it is an ordinary procedure for attorneys, during voir dire, to question prospective jurors about their television viewing habits, as it pertains to CSI. This study will also examine how the producers of CSI discount the effect in its entirety. The creators believe that their creation has been a helpful milestone in the evolution of our criminal justice system.

This dissertation consists of five chapters, each of which focuses on various aspects of the forensic discipline of Firearms and Toolmarks. This dissertation for the most part attempts to highlight the exposure of projectiles to blood and the degradation over time of the fine detail, which is necessary for microscopic examination. This study should be of interest to students and qualified role-players in forensic science, the criminal justice system, the law community and the general population globally. Chapter 1 identifies the research problem and the necessary steps that were taken to ensure that the research methodol.ogy applied is relevant and reliable. Chapter 2 focuses on various factors that have to be considered in damage to bullets and investigation procedures that should be followed to ensure that physical evidence is preserved for submitting to a forensic science laboratory. Chapter 3 investigates the degradation effects of fired bullets exposed to various materials in a laboratory environment and the timelines associated with the degradation effects. Chapter 4 evaluates the examination procedures for fired bullets and the contributing factors that may influence the striation marks on bullets needed for microscopic examination. It also examines the scientific method used for firearm identification, and explores the admissibility of physical evidence in a court of law. The final chapter, Chapter 5 discusses the findings and recommendation of this research study. / Criminology / M. Tech. (Forensic Investigation)

In contemporary crime drama there has been a shift of main character from the forensic scientist to the consultant. This put the representation of knowledge in a different light. In this study the focus is on how, and what kind of cognitive processes and knowledge are represented in two crime dramas with consultants as main characters; CSI: Crime Scene Investigation and Sherlock. Basing the analysis on concepts of cognitive processes and knowledge, it becomes evident that due to the shift in main character the representation of knowledge also has changed; from an institutionalized and science based view on knowledge to the legitimization of a personal, uncritical and fast way of gathering knowledge.

The Medical Examiner of Virginia (ME) dataset and the Virginia Department of Forensic Science Driving Under the Influence of Drugs (DUI) datasets were used to determine whether people have the potential to develop tolerances to diphenhydramine, cocaine, oxycodone, hydrocodone, methadone, and morphine. These datasets included the years 2000-2004 and were used to compare the concentrations of these six drugs between people who died from a drug-related cause of death (of the drug of interest) and people who were pulled over for driving under the influence. Three drug pattern groups were created to divide each of the six drug-specific datasets in order to compare concentrations between individuals with the drug alone, the drug and ethanol, or a poly pharmacy of drugs (multiple drugs). An ANOVA model was used to determine if there was an interaction effect between the source dataset (ME or DUI) and the drug pattern groups. For diphenhydramine and cocaine, an interaction was statistically significant, but for the other drugs, it was not significant. The other four drug-specific datasets showed that the DUI and ME were statistically significantly different from each other, and all of those datasets except for methadone showed that there was a statistically significant difference between at least two drug pattern groups. Showing that all of these datasets showed differences between the ME and DUI datasets did not provide sufficient evidence to suggest the development of tolerances to each of the six drugs. One exception was with methadone because there were 14 individuals that had what is defined as a "clinical 'lethal' blood concentration". These individuals provide some evidence for the possibility of developing tolerances.The main outcomes of this study include suggesting changes to make to the ME datasets and the DUI datasets with regard to the way data is kept and collected. Several problems with the fields of these datasets arose before beginning the analysis and had to be corrected. Some of the changes suggested are currently being considered at the Virginia Office of the Chief Medical Examiner as they are beginning to restructure their database.