After decades with no leads, Sacramento police and the FBI announced several days ago they had arrested a suspect believed to be the Golden State Killer. Joseph James DeAngelo, aged 72, has been living in the same areas terrorized by the Golden State Killer in the 1970s and 80s, and he might have continued to live a quiet and seemingly normal life if not for an online genealogy database. Police reportedly used data from one of these sites to identify DeAngelo as a suspect, later confirming his identity with DNA testing.
The Golden State Killer, sometimes known as the East Area Rapist or Original Night Stalker, was active in California from 1976 to 1986. During that time, police believe he was responsible for at least 50 rapes and 12 murders. After the attacks ended, police were left with no leads. They did, however, have the Golden State Killer’s DNA. All they lacked was a suspect with whom to match it. That’s where the internet comes in.
An example of GEDmatch data.
Of course, DeAngelo was not brazen enough to put his DNA in an online database. Police instead found several distant family members in GEDmatch that shared similarity with the Golden State Killer. From there, it was a simple matter to find people related to those individuals in the right geographic area who matched the profile from decades earlier. That led them to DeAngelo, but it wasn’t enough for an arrest. Police followed DeAngelo in order to collect DNA samples from discarded objects. DeAngelo’s DNA was a match for samples taken from the crime scenes, and police made the arrest.
It’s an unequivocally good thing that the Golden State Killer is behind bars, but some privacy advocates worry about the use of such services to solve crimes. Partial matches from familial DNA can cause police to scrutinize innocent people — this has happened at least once. Eventually, it could deter individuals from providing DNA for research and genealogy purposes entirely.
The outcome of this investigation was a positive for society, but some people will be understandably uncomfortable with police poking around in their DNA to see who among their relations may have committed a crime.
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