It was a landmark achievement with the implication to solve any crime. In March 2018, US police tracked down the Golden State serial killer, who had gone undetected for 40 years, by identifying members of his family on a commercial DNA database. It was the first time investigative genetic genealogy had been used to crack a case and helped spawn a new discipline. Since then, a massive DNA database has been created, tracking almost everyone on Earth. So who should have access to these databases? And under what circumstances?