The Australian peering into the mind of America’s worst serial killer

There have been several advances in DNA technology over Williamson’s career, but she says a recent “gamechanger” has been the growth of genetic genealogy services used to trace family trees. They allow investigators to identify criminals among the relatives of those who upload their DNA profiles.
Joseph DeAngelo, the so-called Golden State Killer, was arrested in April 2018 after police used public genealogy databases to link him to DNA from the crime scenes.
While there are obvious privacy concerns about the practice, Williamson says it is invaluable in solving crimes and providing justice to victims’ families.
“There are 240,000 unsolved homicides in this country and that is too many,” she says. “Everyone’s story deserves an ending.”