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Advances in DNA technology have led to the extremely sensitive and rapid analysis methods used in forensic science. It can often be crucial to a criminal case to unequivocally identify the body fluid source of DNA. This is of particular importance in rape cases where the defence may argue that the source of a female DNA profile might be from a casual touch or from saliva. In this study, proteomics has been employed in an attempt to identify potential biomarkers that are specific to a range of body fluids. Many publications cite the use of proteomics to identify biomarkers of disease such as cancer. In these reports, diseased and healthy tissues or tissues that have been treated or not treated with a drug are compared and the expressed proteins are compared by 2D electrophoresis. Human body fluids differ in function, composition and protein expression. Proteomics therefore seemed an ideal application to isolate the proteins that are characteristic of and specific to, different fluid types. Both saliva and vaginal fluid proteomic methodologies were optimised for sample preparation, IPG strip pH range and protein load, and post-electrophoretic staining. Seventeen isolated protein spots from saliva and vaginal fluid samples were submitted for LC-MS/MS analysis. Nine saliva spots and eleven vaginal spots were identified as known proteins on the MASCOT database. Of those thought to be specific to saliva or vaginal fluid six candidate biomarkers were tested further against a panel of body fluids for specificity using ELISA or Dot Blot. Zinc-α-2 glycoprotein (ZA2G) was detected and present in all body fluid samples thus could be used as a human body fluid positive control in a future assay. SCC (Squamous cell carcinoma) ELISA was capable of distinguishing samples of vaginal origin by detection of SCCA (Squamous cell carcinoma antigen). This antigen could be used in conjunction with a menstrual blood marker to distinguish between vaginal fluid and menstrual blood. Antibody specificity was a limiting factor in the success of the dot blots performed and hence the analysis of Cystatin SA, Cystatin SN and SERPIN B1 was inconclusive.

The qualitative determination of various opiates and benzodiazepines in human serum is described using a two-dimensional gas chromatograph (GC x GC) coupled to a time of flight mass spectrometer (TOFMS). Human serum was 'spiked' with known quantities of benzodiazepines and a 'street heroin' mixture including some of the major metabolites and impurities. The sample components were extracted from the matrix by solid phase extraction (SPE). Constituents containing polar hydroxyl and/or secondary amine groups were derivatised with N-methyl-N-(tertbutyldimethyl) trifluoracetamide (MTBSTFA) to improve the chromatographic performance. The sensitivity and repeatability of the method were evaluated by the preparation of calibration standards for flunitrazepam and its major metabolite 7-aminoflunitrazepam (7-amino- FN), in the concentration range 5-1000 ng/ml. The limits of detection (LOD) and limits of quantitation (LOQ), calculated by repeat injections (x10) of the lowest standard, were 1.6 and 5.4 ng/ml (flunitrazepam); 2.5 and 8.5 ng/ml (7-amino-FN), respectively. A qualitative analysis of hair samples provided by an external collaborator was performed and various drug types detected including opiates, cocaine, methadone and diazepam. The analysis also identified many of the minor components in street drugs which may help forensic scientists to identify the source of the drug. We propose a method to extract and analyse the pseudo-endogenous drug, gamma-hydroxybutyric acid (GHB), in urine, by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Urine samples (<1.62 μg/ml endogenous GHB) were 'spiked' with 10 tg/ml synthetic GHB, extracted using SPE and derivatised with BSTFA. We obtained δ¹³C values for 3 x reference standards (#1 mean -31.7‰; σ_n-1 0.15; n=3: #2 mean -34.0‰; σ_n-1 0.85; n=3: #3 mean -42.2‰; σ_n-1 0.64; n=3). Selective extraction of GHB by affinity chromatography was investigated as a means to improve the sensitivity. A method was developed to synthesise tetrahydro-5-oxo-3-furanyl acetic acid (furanyl acetic acid) which was identified to contain the GHB sub-structure. It was postulated that the reaction of this compound with the lysine residues of a protein would produce an antigen whereby antibodies, with specific binding sites to GHB, could be created.

Two methods for the high performance liquid chromatographic analysis of basic drugs have been studied. In each case the methods have concentrated on separating drugs of forensic interest, based on specially designed test solutions of analytes selected to represent most of the commonly encountered classes of drug compounds. In the first case, a HPLC method was developed on unmodified silica using an aqueous methanolic eluent of high pH. The buffer was prepared from two organic sulphonic acid amines, 3-(cyclohexylamino)-1- propanesulphonic acid (CAPS) and sodium 3-(cyclohexylamino)-2-hydroxy-1- propanesulphonate (CAPSO-Na). The method was shown to be highly reproducible within a single laboratory. The long term stability of the unmodified silica stationary phase was examined, using the newly developed method for the analysis of drugs as a monitor of column performance. Three columns from a single batch of silica were studied, and all showed pronounced changes in retention properties over the period of the study. Similar changes in retention properties were observed for silica stored dry and unused. These results led to the idea that an 'aging process' was changing the nature of the silica surface, probably by a process of hydrolysis of surface siloxanes. This aging process was also believed to be responsible for the appearance of distorted peak shapes for methylamphetamine, although no clearly defined mechanisms could be found to support this idea. In a second study, the application of gradient HPLC methods for the screening ·of a wide range of analytes was examined. In this case, an Inertsil ODS-2 column was used in conjunction with an acid buffered acetonitrile I water gradient. The usefulness of the 1-nitroalkanes as a retention index series was demonstrated and a good level of retention reproducibility was achieved for most analytes studied.

This thesis investigates the reasoning practices of forensic scientists, with specific focus on the application of the Bayesian form of probabilistic reasoning to forensic science matters. Facilitated in part by the insights of evidence scholarship, Bayes Theorem has been advocated as an essential resource for the interpretation and evaluation of forensic evidence, and has been used to support the production of specific technologies designed to aid forensic scientists in these processes. In the course of this research I have explored the ways in which Bayesian reasoning can be regarded as a socially constructed collection of practices, despite proposals that it is simply a logical way to reason about evidence. My data are drawn from two case studies. In the first, I demonstrate how the Bayesian algorithms used for the interpretation of complex DNA profiles are themselves elaborately constructed devices necessary for the anchoring of scientific practice to forensic contexts. In the second case study, an investigation of a more generalised framework of forensic investigation known as the Case Assessment and Interpretation (CAI) model, I show how the enactment of Bayesian reasoning is dependent on a series of embodied, experiential and intersubjective knowledge-forming activities. Whilst these practices may seem to be largely independent of theoretical representations of Bayesian reasoning, they are nonetheless necessary to bring the latter into being. This is at least partially due to the ambiguities and liminalities encountered in the process of applying Bayesianism to forensic investigation, and also may result from the heavy informational demands placed on the reasoner. I argue that these practices, or 'forms of Bayes', are necessary in order to negotiate areas of ontological uncertainty. The results of this thesis therefore challenge prevailing conceptions of Bayes Theorem as a universal, immutable signifier, able to be put to work unproblematically in any substantive domain, Instead, I have been able to highlight the diverse range of practices required for 'Bayesian' reasoners to negotiate the sociomaterial contingencies exposed in the process of its application.

The overall aim of this investigation was to determine whether DNA transfer can be used to identify perpetrators of physical child abuse. To this end two separate investigations were performed: First, 12 areas of the head/neck of 32 children aged 0-5 years of age were swabbed in order to determine the ‘normal’ background levels of DNA present. The results indicated that person-to-person variation accounted for the differences in DNA profiles retrieved, while little non-subject DNA was observed. The second part of the investigation was to determine if DNA is transferred during forceful contact, such as slaps and punches. This half of the study was divided into three phases: firstly 15 volunteers were asked to punch and slap a DNA free acetate sheet attached to a focus pad, 15 minutes after washing their hands. On a separate occasion they were asked to repeat the experiment but with an hour interval between hand washing and contact as well as with three punches/slaps rather than just one. Phase II was a preliminary test of person-to-person forceful contact involving two members of the Forensic Pathology Unit. Finally sixteen volunteers applied single punches/slaps to the upper arm of another volunteer. The results from all three phases indicated that DNA transfer does occur, onto DNA-free surfaces and between individuals, although the profiles retrieved varies between individuals. Slaps resulted in more transfer than punches, while no difference was observed between single and multiple (n = 3) contacts. Many of the volunteers exhibited non-subject alleles of unknown origin on their hands and arms which complicated interpretation. Overall both studies indicated that perpetrators of physical child abuse may be determined by the DNA they deposit during forceful contact although the person-to-person variation observed means further research is necessary in this field.

Pages 199-201 of Appendix I have been removed from the electronic version of this thesis due to copyright restrictions. The full version can be consulted at the University of Leicester Library.

The prospect of an autopsy examination of a loved one is often upsetting for relatives. Despite public perceptions of pathologists, many doctors entering histopathology training do not aspire to undertake autopsy examinations. As many pathologists cease autopsy work following completion of training and the option of an autopsy-light curriculum of UK pathology training is proposed, the future of autopsy practice is unclear. A few research groups, worldwide, have started investigating expansion of the role of post-mortem imaging. The replacement of invasive autopsies by post-mortem imaging is proposed by some as a socially acceptable solution to future autopsy service provision. The benefits of post-mortem computed tomography (PMCT) have been championed but few authors have taken a more critical approach. This thesis critically examines the capabilities of PMCT in the fields of mass fatality investigation and ballistics/projectile deaths. It assesses its ability to replace the invasive components of a forensic post-mortem and the acceptance of such a procedure by the end users of the report. PMCT provides valuable additional information which informs and enhances the autopsy examination. It can form part of the permanent medico-legal record which can be revisited long after body release. The images produced have great potential to revolutionise the demonstration of injuries to end users including HM Coroners, the police, and other legal professions and more importantly lay jurors. PMCT is particularly valuable in the investigation of mass fatalities. It is also of great assistance in the investigation of projectile trauma both as part of the autopsy examination and as a terminal ballistics research tool. Whilst PMCT has a lot to offer death investigations, there are still areas where it cannot compete with the autopsy examination. This is particularly true of certain soft tissue abnormalities. With standard PMCT, vascular abnormalities such as traumatic defects, thrombosis and atherosclerosis cannot be reliably detected as circulating contrast media cannot be seen. Parenchymal defects in organs and cartilage, including penetrating wound tracks cannot be reliably discerned in all cases. At present, PMCT cannot provide all of the answers that the police and legal profession have come to expect from autopsy examinations. The legal profession is not ready to accept the current uncertainties that surround a technique that is very much in its infancy. Therefore, it is unlikely that PMCT will replace the autopsy as the gold standard in suspicious death investigation in the near future. It may have the potential to replace the invasive component of some coronial autopsies in particular some road traffic deaths. It does have great potential as a pre-autopsy screening tool and as a valuable adjunct.

The work presented in this thesis uses contemporary methodology to address three gaps in the current understanding of forensic DNA profiling. Preliminary work was undertaken to identify the most appropriate techniques for use in this thesis, given the equipment available. It was discovered that the QIAamp DNA mini kit was suitable for DNA extraction from most sample types. PicoGreen dsDNA quantitation reagent was proven adequate for quantitation of DNA concentrations greater than 5ng/μl and the AmpFlSTR® SGM Plus™ PCR Amplification system was used for all DNA profile generation. These methods were then used to investigate the effect of peri-mortem blood transfusion on DNA profiling. It was hypothesised that donor leucocytes present in the administered blood products could result in mixed DNA profile generation in post-transfusion blood samples. This hypothesis is rejected after direct analysis of blood products and case examples. The second question addresses the preservation of field-collected biological samples for disaster victim identification using DNA analysis. Two buffer solutions are tested for their ability to preserve soft tissue samples over a period of six months at room temperature. The results of DNA quantification and degradation analysis suggest that both solutions are capable of DNA preservation of 5 – 1000mg muscle tissue over a six month time period, allowing full standard DNA profile production. Finally, this thesis examines the normal background level of non-self DNA present on the adult neck surface by sampling 24 volunteers. These observations are used to investigate whether background levels of non-self DNA interfere with DNA profile analysis and interpretation of physical assault situations. The results do not provide a conclusive answer, but augment our understanding of DNA transfer theory by highlighting the high level of non-self DNA normally present on the adult neck due to adventitious transfer, and the discrepancies from previously published DNA transfer theory.

It is generally accepted that remains should be no more than 75 years old to warrant police interest. Therefore any reliable dating method should distinguish bones from within this interval accurately from those lying outside of it. Although archaeologists have reliable tools for dating material, pathologists have been unable to devise a method that caters for their specific needs. Previous work has focused upon the physiochemical properties of bone or its organic constituents, though the results have failed to produce a workable calibration system. The first hypothesis of this thesis has confirmed the existence of a predictable and measurable relationship between specific radioisotope concentrations in human bone and the post-mortem interval (PMI). It is predicted that the relationship is such that, once a calibration system has been created, it is possible to accurately estimate the PMI in a set of remains of unknown antiquity. Though concentrating upon 210Pb activities, the study also evaluated additional commonly occurring nuclides, both natural and man-made, the latter being subsequent to nuclear experimentation. The second confirmed hypothesis is that the geographical region an individual lived within becomes imprinted within their skeletal system, such that recognisable relationships between isotopes exist, creating a radio-isotope fingerprint. Examination of these relationships allows identification of the country in which a decedent lived.