Purpose The purpose of this paper is to describe the discovery of the application of DNA profiling to the criminal justice system. Design/methodology/approach Researching the origins of the discovery of the application of DNA to the criminal justice system via an analysis of the first case in which it was applied to. Findings It was discovered that the first application of DNA profiling to the criminal justice system meant that a young man with intellectual disabilities was saved from wrongful prosecution. The case study also raises ethical issues concerning the mass screening of targeted populations by way of DNA. Originality/value The case study is descriptive in nature and draws from earlier work describing the events which unfolded.