DNA-bevisningens brister : En undersökning av invändningar om sekundäröverföring av DNA-spår och dess genomslagskraft i straffprocessen

Sammanfattning: A number of people have criticized the fact that courts often over-rely on DNA- evidence and that the shortcomings of DNA-analyses are rarely addressed. One flaw with DNA-analyses is that they cannot distinguish whether the presence of the DNA-trace has been caused by a so-called secondary transfer. Secondary transfer, the occurrence of which has been confirmed by several scientific stud- ies, means that DNA is transferred in two stages via contacts. A transfer of DNA can thus first occur from one person to another, for example by shaking hands, and then from the other person to a material, for example by grabbing a weapon. This poses a risk that DNA from an innocent person can be transferred through another person to a crime scene. A fundamental principle of criminal procedure is that the full burden of proof should be placed on the prosecution. This principle is derived from the presump- tion of innocence in Article 6.2 of the ECHR. As a consequence, the defendant has a right to remain silent throughout the judicial proceedings. Should the de- fendant instead be required to explain some of the circumstances of the case, a burden of proof would fall on the defendant, a so-called burden of explanation. Thus, a requirement that the defendant explain some of the circumstances of the case conflicts with the principle of the prosecutor's full burden of proof. Given the criticism that the courts rarely consider the shortcomings of DNA- evidence, there is a risk that the responsibility falls on the defendant to point out that a secondary transfer of DNA has occurred and to actively work towards convincing the court of his or her innocence. The purpose of the paper is thus to investigate the courts' consideration of these objections from the accused. The question is if a burden of explanation is placed on the accused and whether this is compatible with the presumption of innocence. To fulfill the purpose, an empirical study was conducted in the form of an analysis of 16 district court and appellate court decisions. The results showed that the defendant was imposed a burden of explanation in several cases. An exami- nation of the case law of the ECHR showed that there is, in exceptional cases, a possibility to impose an explanatory burden on the accused. However, the cases in the study were not covered by the exception. In conclusion, the practical ap- plication of the burden of proof is not compatible with the presumption of in- nocence. There is thus a need to educate judges on the complex subject of DNA to draw attention to the drawbacks of the evidence and to correct the false per- ception of DNA evidence as infallible. Furthermore, there is a need for a new precedent from the Supreme Court clarifying how the burden of explanation should be applied in accordance with the ECHR.