Personal Genetics Education Project

Golden State Killer and DNA databases: Dr. Johnny Kung’s interview

With the arrest of a suspect in the case of the notorious Golden State Killer, aided in part by the use of a genealogy website called GEDMatch, questions of privacy and consent around DNA are front page news.

While details of the investigation have not been completely released, the basic outline is likely to be that the police created a genetic profile using a stored DNA sample from one of the crime scenes tied to the killer. They then used GEDMatch – where genealogy researchers and enthusiasts voluntarily upload their raw DNA test results – and found partial matches who are third to fourth cousins of the killer. By performing a familial search, the police were able to zero in on a suspect, who they then confirmed by matching with DNA from an item that the suspect discarded.

For more about how forensic DNA and familial searching are used in criminal investigations, and the benefits and implications of such applications, see pgEd’s page on genetics, law enforcement and crime.

pgEd’s Dr. Johnny Kung joined WGBH’s Jim Braude to discuss the scientific and privacy-related issues of this case.