Criminal and Medical Law

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Browsing Criminal and Medical Law by Subject "Admissibility"

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    First generation forensic evidence and its influence on legal decision-making: a South African perspective
    (University of the Free State, 2013) Visser, Jo-Marí; Oosthuizen, H.; Verschoor, T.
    English: Interactions between science and law can be dated back as far as 9000 B.C. to 3000 B.C., to a time known as the Neolithic age. By the seventeenth century, great scientific contributions by, amongst others, Copernicus, Galileo, Newton, and Boyle affected the way the world was viewed and what methods were most appropriate for finding the truth and, specifically, altered the thought processes of the entire literate English society, including English jurists. During the seventeenth century in England, the fields of law and science enjoyed increased awareness of the probability of truth, not the certainty of it. The search for absolute truth was thus replaced by probabilistic hypotheses and assessment of evidence to achieve truth beyond a reasonable doubt. The interconnectedness of science and law has diminished over time as contemporary thinking demanded not only greater specialisation in the profession and its subdivisions, but also a greater autonomy of legal thought and reasoning. Practitioners, scholars and authors held the view that legal reasoning is, and should remain, separate from scientific reasoning. Modes of reasoning employed in criminal investigation and judicial decision-making are communal in both science and law. Additionally, investigating officers frequently employ forensic science and scientific evidence to assist and direct them in criminal investigations. In the same manner, prosecutors apply forensic evidence in order to assist the court in finding the truth, and to ultimately prove its version of criminal events. In South Africa, police investigators and state prosecutors typically rely on eyewitness testimony in both the detection of crime and to achieve successful conviction of guilty offenders. In addition, DNA evidence has emerged as the golden standard of forensic evidence and much reliance is placed on the results of DNA profiling. However, eyewitness testimony is notoriously unreliable and DNA evidence is not the infallible assurance of certainty it was once thought to be. It is trite that presiding officers must be provided with all relevant and admissible evidence in criminal trials. This includes traditional forensic sciences like bloodstain pattern analysis, trace evidence, fingerprint evidence and many more. Recent research has revealed the questionable scientific foundations of these traditional forensic sciences. While the scientific community is working towards stabilising these knowledge bases, provisions of the law of evidence must provide adequate instruments to prevent the admission of ‘junk’ science into evidence. Yet an examination of a variety of rules of admissibility reveals a deficiency in the law to competently exclude fallible and unreliable forensic evidence. In the South African criminal justice system presiding officers invest great reliance on the opinion and explanation of expert witnesses without critically assessing the scientific validity of the testimony. This has resulted in the admission of faulty evidence. To mend this problem presiding officers, as well as investigating police and legal practitioners must obtain a solid scientific knowledge base to enable these role-players to accurately assess forensic evidence.
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    'n Regsvergelykende studie van deskundige getuienis in straf- en siviele verhore
    (University of the Free State, 2007-11) Knoetze, Izette; Oosthuizen, H.; Van der Merwe Fick, C. P.
    English: Progress in the field of science requires more and more the use of experts as witnesses during legal proceedings. It is due to the complex nature of some scientific principles that legal practitioners make use of expert witnesses to answer their questions and to supply them with reasons for their answers as well. Due to their expertise and/or experience, expert witnesses are in a position to explain to the courts complex concepts and to help the courts in their understanding and interpretation of scientific principles. Courts, however, have a discretion to reject evidence by expert witnesses should the court be of the opinion that such evidence is irrelevant and unreliable or if the witness failed to substantiate, to the satisfaction of the court, the reason for his or her opinion. The report of the expert witness contains an exposition of the reasons on which he or she basis his or her opinion. The report has the further use that it affords the court a chance to subject it to cross-examination. Aspects on which expert witnesses may testify is legion. Examples discussed above include among other things evidence regarding deoxyribonucleic acid testing on blood samples taken from a victim of crime, evidence extracted by means of a polygraph test, evidence regarding fingerprints, earprints, brain fingerprinting and thermal imaging. Evidence by psychologists and psychiatrists is an important aid should a court, for example, have to decide on the custody and access of minors after divorce. Interception and/or tapping of cellular and/or telephone conversations is a relatively simple and fast way to obtain evidence during the investigation of an alleged offence. In this regard, the Bill of Rights calls for a weighing of interests of the right to privacy (of the accused) and the public interest (the maintaining of law and order). Legislation regulates most matters concerning expert evidence. Case law should provide guidelines to the courts in their evaluation of expert evidence. If an expert witness presents evidence regarding an unknown scientific technique to the court, the courts should look to international case law for guidance. American case law laid down principles that should be met before evidence regarding an unknown scientific technique is presented in court and may serve as guidelines to South African courts. Factors such as the reliability and acceptance of a technique in scientific circles both play a role in the adjudication of the question concerning the admission and/or rejection of evidence as far as that technique is concerned.