DNA evidence under the microscope: Why the presumption of innocence is under threat in Ireland

Abstract

DNA is formidable evidence which is becoming increasingly relied upon by the prosecution in Ireland. In many jurisdictions, courts and criminal investigators have been quick to seize upon its probative power-apparently slow to acknowledge the potential for fallibility. Yet despite DNA’s clear advantages, research demonstrates that the interpretation of certain DNA mixtures may be subject to bias. What is more, the scientific community continues to warn that there is still no definitive frame of reference for interpreting certain mixed DNA profiles. There are two additional problems running parallel to this in Ireland. First, the presumption of innocence is marginalised in the jurisdiction. Second, the Criminal Justice (Forensic Evidence and Database System) Act 2014 raises a number of human dignity and rights concerns which present the ancient legal precept of presumed innocence with even further challenges in Ireland. The purpose of this chapter is therefore to investigate the extent to which DNA evidence imperils the presumption of innocence in Ireland.