Everybody has that relative they don't talk about because of some skeleton in the closet.
Or maybe the family tree digs up an awful ancestor everybody would just as soon forget. Go back far enough, and you're bound to find a killer or two.
In the Golden State Killer case, genealogy found a mass murderer. In criminal technology, it pretty much changes the meaning of "family reunion."
Genealogy and DNA
According to reports, police cracked the case by searching online genealogy sites. They already had DNA from a crime scene years ago, and found some distant relatives of their suspect online.
The Sacramento District Attorney's office said the key lead came from "various websites that cater to individuals wanting to know more about their family backgrounds by accepting DNA samples from them."
Investigators drilled down to the Sacramento area, and found their suspect. DNA tests confirmed a match to more than 10 murders in California.
Joseph James DeAngelo was then arrested and booked on two counts of murder. Authorities expect to charge him in 12 homicides in Sacramento, Orange, Santa Barbara, and Ventura counties.
In addition to the murders, DeAngelo is suspected of committing at least 51 rapes. The crimes began in 1974 and gained national attention because the victims were often tortured in sadistic rituals.
After his arrest, the case became more sensational because DeAngelo is a former police officer. It was also eerily coincidental because a book about the crime spree had just been published.
Michelle McNamara's book, "I'll Be Gone in the Dark," debuted at the top of the New York Times' bestseller list last month. It was published posthumously and predicted DeAngelo's end.
"This is how it ends for you," she wrote. "You'll be silent forever, and I'll be gone in the dark..."