What happened was that the police was using some publicly available data to cross reference with cold cases. Then when they found a familiar match, the produced a warrant to get the identity of the family member that was registered. The main issue was that the info was available, so some tech just ran the comparison. However, it feels like it would be way to easy to request the information directly with a warrant and that's it. Using something like: "We need to save the women and children, here is a list of unidentified DNA samples, please compare them to all your database."