The Golden State Killer was caught after police detectives uploaded his DNA to a personal genomics website in 2017 pretending it was theirs.
That's untrue. They uploaded it to Gedmatch which is the one website that allows these things. They didn't 'pretend it was theirs', they legitimately uploaded it from a police account. They do this a lot but you need to opt in now due to the legal challenges. They've solved quite a few crimes and identified many unidentified bodies, including a number of murdered children.