On The Judicial Determination Of DNA Evidence

In recent years, DNA evidence has been widely used in facts identification of criminal cases, and has been known as "the king of evidence" because it provides a great help for the detection of the cases. From the perspective of evidence law, if an evidence is admissible, it must meet the conditions of legitimacy, objectivity and relevance. DNA evidence, one of scientific evidences, is easily identified as the key evidence in practice, so the standard of acception should be more stringent than general evidences, guaranteeing exact management in every periods including sample collection, delivery, custody, identification. However, the DNA identification appraisal itself is a probabilistic result, rather than a definitive conclusion, and the process of appraisal and identification is influenced by human factors, so that DNA evidence is not as unquestionable as people think. In terms of our judicial practice,both sides and even judges rely too much on DNA evidence,and there is a tendency of insufficient cross-examination and formal investigation. Therefore, this thesis analyzes identification procedure of DNA evidence systematically from both theoretical and practical aspects , and try to put forward some advice in identification standards and system construction.The first part is an overview of judicial identification of DNA evidence. Starting from the concept and property of DNA evidence, this thesis explores its scientific basis, analyzes its unique proof value and litigation value in the field of criminal justice, and points out the necessity of strengthening the judicial identification of DNA evidence.The second part is about external research of judicial identification of DNA evidence, including UK, America and Germany. Besides general legislation, this thesis introduces some representative rules and systems of the three countries,including the defense's right to know in pre-trail period and rules of cross-examination in the trail in Briton,the American DNA evidence admittance standard and the expert witness system, and the German procedures of DNA sample collection and rules about judicial appraiser.The third part is about the investigation and identification of DNA evidence. This thesis analyzes the cognition risk of DNA evidence to indicate that DNA evidence is not an irrational "irrefutable evidence", and gives feasible advice about how to make identify DNA evidence from the competency and probative force of DNA evidence.The fourth part is about the system improvement in identification of DNA evidence. After pointing out the problems in current DNA identification procedure,this thesis puts forward that it is necessary to gradually improve the system of judicial appraiser appearance and system of expert assistant. At the same time, the system of cross-examination should be reformed in order that the two sides can make effective cross-examination and the authenticity and reliability of DNA evidence can be guaranteed.Through the reconstruction of the identification standard and improvement of related procedures, the substantive process of investigating DNA evidence will be promoted, which results in scientific identification of case facts and scientific trial ultimately.