Golden State Killer: The Case That Proved Genetic Genealogy Works

The Hunt Before the Upload

For four decades, the man California law enforcement called by three different names operated as three separate investigations. The Visalia Ransacker committed more than 100 burglaries in Tulare County between 1973 and 1975. The East Area Rapist attacked at least 51 women in Sacramento, Contra Costa, and Stanislaus counties between 1976 and 1979. The Original Night Stalker murdered ten people across Santa Barbara, Ventura, and Orange counties between 1979 and 1986. DNA linked the three case files in 2001, confirming what veteran detectives had long suspected, but the same DNA profile that tied the crimes together could find no match in any law enforcement database. The case sat for another 17 years.

Paul Holes, a cold case investigator with the Contra Costa County District Attorney’s office, had worked the file since 1994. He had submitted the profile to CODIS repeatedly. He had chased tips to exhaustion. In late 2017, he and FBI forensic specialist Steve Kramer made a decision that would rewrite the methodology of cold case investigation: they would upload the killer’s DNA profile to GEDmatch, a public genealogy database where users share their raw DNA data to find relatives. The database was never designed for law enforcement use, and its terms of service did not explicitly forbid it.

The Three-Month Hunt

The April 2018 upload produced matches to third and fourth cousins of the unknown suspect. Barbara Rae-Venter, a retired patent attorney who had taken up genetic genealogy as a hobby, built twenty-five family trees from the match list and identified a shared ancestor in the early 1800s. Working forward, she eliminated candidates by age, sex, geography, and physical description until a single branch remained. Joseph DeAngelo fit every filter: a white male of the right age, a former police officer whose law enforcement training would explain the killer’s counter-forensic discipline, a resident of Sacramento and Citrus Heights during the attack windows.

Sacramento County deputies collected two discarded DNA samples from DeAngelo’s property, a tissue from his trash and a swab from his car door handle, and confirmed the match within 72 hours. He was arrested on April 24, 2018 while retrieving a piece of fishing line from his garage. He pleaded guilty on June 29, 2020 to thirteen counts of first-degree murder and was sentenced to consecutive life terms without parole.

What the Case Proved

The Golden State Killer arrest established investigative genetic genealogy as a functional law enforcement technique and triggered a wave of arrests in cases that had been cold for decades. Within twelve months of DeAngelo’s arrest, genealogist CeCe Moore and the Parabon NanoLabs team had identified suspects in more than fifty additional cases. The Bear Brook murders in New Hampshire and the Boy in the Box in Philadelphia both fell within three years. The broader landscape of cold cases solved by genetic genealogy passed 650 resolved investigations by late 2023.

The case also forced a legal reckoning. GEDmatch and FamilyTreeDNA rewrote their terms of service to explicitly govern law enforcement access. The Department of Justice issued interim guidelines in 2019 restricting the technique to violent crimes and unidentified remains after traditional methods are exhausted. Several states introduced legislation requiring judicial oversight of genealogy searches, and Maryland became the first state to pass comprehensive regulation in 2021. The questions the method raises about genetic privacy, consent by relation, and the scope of the Fourth Amendment remain unresolved.

DeAngelo is 80 years old. He will die in Corcoran. The method that caught him is still being refined, and the list of suspects it is about to name is still being built.