After more than 40 years, the teenage murder victim known as "Precious Jane Doe" has finally been identified, bringing solace to her grieving family
Elizabeth Ann Roberts
Elizabeth Ann Roberts
| Credit: Snohomish County Sheriff's Office

Snohomish County, Washington, detective Jim Scharf never gave up trying to identify the 17-year-old murder victim he came to call “Precious Jane Doe.”

Now, after years of investigative work, the victim has been identified as Elizabeth “Lisa” Ann Roberts of Roseburg, Oregon, the sheriff’s office says in a statement.

“It was wonderful feeling to finally locate Lisa’s family,” Scharf tells PEOPLE. “She actually had two families wondering what happened to her, a biological family and an adopting family,” he says.

Scharf and the Snohomish County Sheriff's Office Major Crimes Unit, its Cold Case Team, and the Snohomish County Medical Examiner's Office, worked with investigative genetic genealogist Dr. Barbara Rae-Venter to help identify Roberts.

The DNA used for the identification was obtained from Roberts’ hair using a new scientific technique developed by scientist Dr. Ed Green that was “previously thought to be impossible,” the sheriff’s office says.

Roberts will be buried in the Pine Grove Cemetery in Hood River, Oregon, Scharf says.

“Both families have relatives there, so Lisa is finally on her way home, where she is loved," he says.

Detective James H. Scharf
Det. Jim Scharf
| Credit: Snohomish County Sheriff's Office

Born in 1959 as Elizabeth Ann Elder of Hood River, Oregon, the victim was adopted when she was about two years old and renamed Elizabeth Ann Roberts.

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On July 25, 1977, she ran away from home, calling her parents from Everett, Wash., to ask for money.

Fifteen days later, on August 9, 1977, she was murdered.

Her body was found 5 days later by locals who were picking blackberries in Everett.

Detectives at the time learned that Roberts was hitchhiking near Silver Lake on August 9, 1977, the sheriff’s office says.

David Roth, who was 20 at the time, told police he picked her up and asked her to have sex. When she refused, Roth strangled her with a bungee cord and shot her seven times in the head, dumping her body in a wooded area.

He confessed to the murder and was sentenced to 26 years in prison. Released in 2005, he died of cancer on Aug. 9, 2015, 38 years “to the day” after he killed Roberts, The Daily Herald reports.

Despite his conviction, investigators were unable to identify the victim, who was previously believed to have been between 25 to 30 years old.

A New Name for Jane Doe

In 2008, Scharf began working on the case as its lead detective, after the Doe Network inquired about the status of the case, the sheriff's office says.

Roberts’ body was exhumed and examined by state forensic anthropologist Dr. Kathy Taylor, who determined the victim was a 16- to 19-year-old girl.

But she still had no name.

“It struck my heart," Scharf told Q13Fox. "I knew there's got to be people out there who love her. She's precious to me, just like she must've been precious to them, so that's why I named her Precious Jane Doe."

Over the years, Scharf continued working on the case, enlisting the help of Green and Rae-Venter and others.

On June 16, when the Oregon Health Authority gave Scharf the final confirmation of Roberts’ identity, he called her family to share the news.

“When it all came together and we finally found her name I couldn’t wait to tell the family,” he tells PEOPLE.

“It was hard to believe we found them. It is slowly sinking in.”

When Roberts' sister sent him a picture of her, he said, he was “so happy” to finally see what she looked like.

“She is precious,” says Scharf, who for years included a link in his email signature, saying,  “Help us identify our precious Jane Doe.”

“So many people do care about her, like I knew they would,” he says. It was emotional yesterday, seeing two of her biological half-siblings on TV and hearing the outpouring from the community that they are so happy this case was finally solved.

“It’s a sad story, but she will be at peace now, which is good.”