The rape and murder of a 20-year-old Oregon woman nearly 40 years ago has been solved using DNA and forensic genealogy, cold case detectives said -- but her accused killer isn't around to face justice.

Anna Hlavaka had been murdered in Portland in 1979 and on Thursday authorities announced her killer was a man who was executed in Texas in 1999 for raping and strangling a cheerleader.

Detectives said they tied Jerry McFadden to Hlavaka’s murder after submitting DNA from the crime scene to the public GedMatch website for genealogical analysis. The same website was used last year to help solve more than two dozen cold case murders and rapes, including the notorious Golden State Killer case in northern California.

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“Honestly, without this technology we would have never solved this case,” Oregon Police Cold Case Detective Meredith Hopper, the lead investigator in the Hlavaka case, according to FOX12 Portland.

During the investigation, Hopper and her partner Detective Brendan McGuire learned McFadden traveled to the Pacific Northwest in 1979 with an acquaintance when he was on parole in Texas for yet another rape.

“Honestly, without this technology we would have never solved this case,” — Oregon Police Cold Case Detective Meredith Hopper.

Hlvaka was killed July 24, 1979 after working a shift at a nearby McDonald’s, the station reported. She had been strangled with an electric cord from a clock radio. Her sister found the body.

“She was described by those who knew her as being a well-mannered young lady,” Oregon police said of the victim.

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McFadden was convicted of strangling 18-year-old cheerleader Suzanne Harrison, of Hawkins, Tex., with her underwear in 1986, police said. He also shot and killed her two friends.

His DNA was never entered into an FBI database for comparison to unsolved crimes due to his status as a death row inmate, police said.

McFadden, who called himself “Animal,” died gasping and sputtering, according to reports at the time of his execution by lethal injection.

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One of the needles in his right arm was placed just above a large tattoo of a satanic face, the Austin American-Statesman reported in 1999.