Defence Rights in the Context of Huge Data Sets and Big Data Forensic Tools in Criminal Proceedings

Abstract

Criminal cases increasingly revolve around extensive data sets consisting of digital evidence and advanced technological search tools such as Hansken, a big data forensic tool developed by the Netherlands Forensic Institute. In this context, lawyers and scientists have already argued that advanced search tools significantly strengthen the position of the prosecution at the expense of the defence, which generally does not have access to these tools. As a result, the defence has little influence to help determine what counts as relevant information in a criminal case and has hardly any possibilities to find exculpatory evidence and to test the reliability of digital evidence. This in turn leads to significant power and knowledge asymmetry. The principle of equality of arms as a core part of the right to a fair trial in Article 6 of the European Convention on Human Rights provides a good basis for the development of new or more extensively interpreted defence rights that are needed in the digital age. Based on an analysis of recent ECtHR case law, I discuss the level of established rights of the defence with regard to access to the dataset(s) and the advanced search tool in criminal proceedings. Thinking further as to the possible and desirable procedural guarantees in this novel context, I then discuss how the reliability of digital evidence and the process though which it was produced can be ensured and tested by the defence through a logging obligation and a right to counter-expertise.