Joseph James DeAngelo

Joseph James DeAngelo was a former police officer in Auburn and Exeter, California who was charged with eight counts of first-degree murder, with special circumstances. On May 10, the Santa Barbara County District Attorney's office charged DeAngelo with four additional counts of first degree murder for the four killings believed to be committed by the Golden State Killer in that county.

Before the arrest, law enforcement uploaded the Golden State Killer's DNA profile from an intact rape kit in Ventura County to Florida-based personal genomics website GEDmatch. The website identified 10 to 20 distant relatives of the Golden State Killer, sharing the same great-great-great grandparents, from whom a team of five investigators constructed a large family tree. They identified two suspects in the case, one of whom was ruled out by a relative's DNA test, leaving DeAngelo as the main suspect. Investigators acquired samples of his DNA from items he discarded outside his home, one of which definitively matched that of the killer. The process took about four months, from when the first matches appeared on GEDmatch to when DeAngelo was arrested.