SACRAMENTO, Calif. >> Investigators hunting down the so-called Golden State Killer used information from genetic websites last year that led to the wrong man, court records obtained today by the Associated Press showed.

An Oregon police officer working at the request of California investigators persuaded a judge in March 2017 to order a 73-year-old man in a nursing home to provide a DNA sample. It’s not clear if officers collected the sample and ran further tests.

The Oregon City man is in declining health and was unable to answer questions today about the case.

The case of mistaken identity was discovered as authorities hailed a novel use of DNA technology that led this week to the arrest of former police officer Joseph DeAngelo at his house outside Sacramento on murder charges. Critics of the investigative approach, however, warned it could jeopardize privacy rights.

DeAngelo’s suspected of being the sadistic attacker who killed 13 people and raped nearly 50 women during the 1970s and ’80s.

Handcuffed to a wheelchair in orange jail scrubs, DeAngelo made his first court appearance today. The 72-year-old looked dazed and spoke in a faint voice to acknowledge he was represented by a public defender. He did not enter a plea.

He has been charged with eight counts of murder, and additional charges are expected, authorities said.

“We have the law to suggest that he is innocent until he’s proven guilty and that’s what I’m going to ask everyone to remember,” DeAngelo’s public defender Diane Howard said outside court. “I feel like he’s been tried in the press already.”

Investigators were able to make the arrest this week after matching crime-scene DNA with genetic material stored in an online database by a distant relative. They relied on a different website than they had in the Oregon search, and they did not seek a warrant for DeAngelo’s DNA.

Instead, they waited for him to discard items and then swabbed the objects for DNA, which proved a conclusive match to evidence that had been preserved more than 30 years.

Also today, the co-founder of the genealogy website used by authorities to help identify DeAngelo said he had no idea its database was tapped in pursuit of the suspect who eluded law enforcement for four decades.

Authorities never approached Florida-based GEDmatch about the investigation that led to DeAngelo, and co-founder Curtis Rogers said law enforcement’s use of the site raised privacy concerns that were echoed by civil liberties groups.

The free genealogy website, which pools DNA profiles that people upload and share publicly to find relatives, said it has always informed users its database can be used for other purposes. But Rogers said the company does not “hand out data.”

“This was done without our knowledge, and it’s been overwhelming,” he told The Associated Press.

For the team of investigators, GEDmatch was one of the best tools, lead investigator Paul Holes told the Mercury News in San Jose.

Officials did not need a court order to access GEDmatch’s large database of genetic blueprints, Holes said. Major commercial DNA companies say they do not give law enforcement access to their genetic data without a court order.

Civil libertarians said the practice raises legal and privacy concerns for the millions of people who submit their DNA to such sites to discover their heritage.

Privacy laws aren’t strong enough to keep police from accessing ancestry sites, which have fewer protections than regulated databanks of convicts’ DNA, said Steve Mercer, chief attorney for the forensic division of the Maryland Office of the Public Defender.

“People who submit DNA for ancestors testing are unwittingly becoming genetic informants on their innocent family,” Mercer said.

While people may not realize police can use public genealogy websites to solve crimes, it is probably legal, said Erin Murphy, a DNA expert and professor at New York University School of Law.

“It seems crazy to say a police officer investigating a very serious crime can’t do something your cousin can do,” Murphy said. “If an ordinary person can do this, why can’t a cop? On the other hand, if an ordinary person had done this, we might think they shouldn’t.”

While most consumers would submit DNA to a commercial company such as Ancestry.com and 23andMe to create a genetic profile, the FBI did so for investigators, Holes told The New York Times.

The profile was then uploaded to GEDmatch using a fake profile and pseudonym, the Times reported. The site allows users to remain anonymous.

A year earlier, Holes had identified a rare genetic marker in the assailant’s DNA. He entered the information among 189,000 profiles at the genealogy website, YSearch.org, and the results led to a relative of the Oregon man.

A spokeswoman for FamilyTreeDNA.com, which operates YSearch.org, said the company wasn’t contacted by law enforcement.

“While we take our customers’ privacy and confidentiality extremely seriously, we support ethically and legally justified uses of groundbreaking advancements of scientific research in genetics and genealogy,” company officials said in a statement.

Sacramento District Attorney Anne Marie Schubert told AP she was unaware of the Oregon misfire and, as far as she knows, genealogical sites weren’t used before DeAngelo was identified.

DNA was just coming into use as a criminal investigative tool in 1986 when the predator also known as the East Area Rapist apparently ended his decade-long wave of attacks.

As a former police officer, DeAngelo probably would have known about the new method, experts said.

Police at the time suspected they were chasing a fellow cop or armed services member because he was so methodical and meticulous, said Wendell Phillips, a former Sacramento deputy who joined the hunt for the rapist who terrorized the suburbs east of the state capital.

In fact, officers assigned to a special task force were required to submit saliva samples to exclude anyone who shared a genetic trait, Phillips said. About 85 percent of people secrete their blood type in saliva and body fluids, but the rape suspect was in the roughly 15 percent who didn’t.

“Obviously, you didn’t want the East Area Rapist on the team,” Phillips said. “That turned out to be a pretty good concern.”