“The investigators used an open-source genetic database, GEDmatch, to explore family trees and see whether any contained matches to DNA samples from the crime scenes, according to Paul Holes, a retired cold case investigator who briefed the Sacramento County sheriff throughout the final stages of the investigation.
Once a family profile was created, the investigators could find feasible “suspects” within a family.”
See What the Golden State Killer case means for your genetic privacyThe case of the Golden State Killer is fascinating. It began when I was a young man and may conclude shortly. The killer left a few samples of DNA which have been preserved well enough to be matched decades later. Family members of the killer entering their DNA profiles into various databases lead to finding a familial match which by process of elimination lead to the killer. This is a huge positive benefit to society and victims of crime but opens the door to horrible abuses. What if Hitler had such technology? What if DNA samples were compulsory for everyone? What if a tyrant wanted to wipe out whole families or communities to suppress dissent? This gives a whole new meaning to ethnic cleansing or eugenics.
Legally this hinges on the right not to “self-incriminate” but DNA is mobile and people can voluntarily give up samples or be forced by the courts for probable cause. I hope it’s as simple as nailing down “crime doesn’t pay” to greater certainty and not the doorway to horrors unknown. It’s certainly great use of DNA-tinkering and information technology, paths I’ve recommended for students for decades.