The technique -- which was instrumental in leading to the arrest in Los Angeles of an accused mass murdered known as the Grim Sleeper -- involves using DNA from crime scenes to search databases for people who are related to the source of the DNA.
Cold case investigators in Orange County did a familial search to identify a man who raped and killed Lynda Susan Saunders and wounded another man in 1978. DNA retrieved from Saunders' body of led investigators to conclude last month the killer was James Lynn Brown, who committed suicide in 1996, The Orange County Register reported Tuesday.
"This case would not have been solved without the familial searches because the suspect is deceased and his DNA sample never went into the database," said Mary Hong, a forensic scientist at the Orange County Crime Lab.
However, Michael Risher, a lawyer with the American Civil Liberties Union of Northern California, told the newspaper the California Legislature has not authorized use of the technique, "so we have the search procedures conducted based on a memo that the Department of Justice developed."
Risher said using familial search techniques overlooks constitutional protections, including a requirement that police obtain search warrants.
California Department of Justice spokeswoman Michelle Gregory said the state restricts use of familial searching to cases of homicide and sexual assault involving serious risk to public safety, and it may be used only when all other investigative leads have been pursued. She said the state can "perform familial searches in a manner that balances the rights of individuals with society's interest in solving crimes."
California is one of three states where the technique is in use, the Register said.