Results of the DNA test showed the man accused of being the "Golden State Killer" was not involved in one of the cases in which he was a suspect.
The Golden State Killer
The Golden State killer terrified California in the 1970s and 1980s with murders, rape, home invasions, and burglaries.
Last year, more than three decades after these events happened, investigators tracked down former policeman Joseph DeAngelo based on DNA found at the crime scenes and data on genealogy websites.
The septuagenarian has been charged with 13 counts of murder and kidnapping. One of these cases is the 1975 murder of 14-year-old Donna Jo Richmond near Exeter, California.
Prosecutors on Tuesday, however, said DeAngelo has been cleared of involvement. The District Attorney's conviction review report said DNA profile from a sample taken from Richmond's body does not match DeAngelo's genetic profile.
Prosecutors now stand by the conviction of Oscar Archie Clifton for the murder. Clifton, who has always maintained his innocence, died in prison in 2013 while serving a life sentence.
Hunting Criminals With Genetic Genealogy
More than 12 million Americans have embraced genetic testing to learn about their health risks and explore their family origins. The process involves sending spit samples to genealogy companies such as 23andMe or AncestryDNA.
Individuals who have had their DNA tested and want to find relatives who were tested by a different company can upload their results to the open data personal genomics database GEDMatch. Investigators now use GEDMatch to locate suspects of rape and murder cases.
GEDMatch was instrumental in the arrest of DeAngelo in April last year. Using samples from the crime scenes, police found DNA matches in GEDMatch to third cousins of DeAngelo.
After exploring online family trees, investigators identified DeAngelo as the likely suspect because he lives in areas that the Golden State killer terrorized and is in the right age group of the suspect.
DeAngelo's DNA samples taken from items he had thrown were later found to be a direct match to those at the murder scenes.