Her murder went unsolved for nearly 40 years. Then DNA pointed to a serial rapist named 'Animal.'

Rose Ann Hlavka came home to the modest brick apartment building just northwest of Portland, Oregon's downtown around 10 pm expecting to find her 20-year-old sister, Anna Marie. The siblings not only shared a home but they both worked at a nearby McDonald's, where Anna Marie Hlavka had finished a shift a few hours earlier.

But her sister didn't answer when Rose Ann opened the door and called her name on that night, July 24, 1979. She soon discovered why: Anna Marie was sprawled dead in the bedroom. She had been strangled and sexually assaulted.

For four decades, Portland police were baffled by the brutal crime against the young woman with flowing brown locks and a bright smile. Blood samples were analyzed. Polygraphs were administered. Suspects were grilled and released. The case went cold - that is, until last week.

Portland police announced Thursday that improbably intact DNA saved from under Anna Marie's fingernails had at last pinpointed her killer, a man police had never suspected: Jerry "Animal" McFadden, a notorious serial rapist and murderer from Texas who once inspired one of the state's biggest ever manhunts.

The shocking announcement of McFadden's role in a crime 2,000 miles away from his usual territory brought an unexpected end to Hlavka's mysterious killing. It also marked the latest triumph for a new, controversial branch of DNA testing that has used public genealogy sites to close scores of lingering cold cases, while identifying high-profile suspects like the Golden State Killer.

"Without this technology, we never would have solved this case," Portland Police Detective Meredith Hopper told reporters on Thursday.

"All of his criminal history and police contacts and even address information is all from about three counties in Texas. There was never any link to him coming up here. ... He never would have risen to the level of a suspect."

In the hours after Hlavka's sister found her body, Portland detectives combed the neighbourhood for witnesses. They found a co-worker who had last seen her alive that day around 5 pm outside her apartment. They interviewed countless suspects. And, crucially, they kept and carefully stored forensic evidence from the scene.

But no one emerged as a credible suspect. Weeks stretched into years and then into decades.

New DNA techniques

In 2009, Portland police sent old evidence to the state crime lab to see if new DNA techniques might turn up any leads. Two years later, Janelle Moore, a senior forensic scientist with the Oregon State Police Crime Lab, made a remarkable discovery: A full DNA profile from an unidentified man she was confident was the killer.

Jerry 'Animal' McFadden had been convicted of two counts of rape in 1972 in Texas.

"It was surprising when we got the initial results," Moore told reporters on Thursday.

"It continues to be a landmark cold case for me from a scientific perspective, that we can get a profile from evidence that is so, so old."

Detectives eagerly uploaded the information to CODIS, the FBI's national database for DNA. There was no hit. Whoever had assaulted Hlavka had never been entered into the directory.

In 2012, Hopper took over the case and began trying to match the DNA profile with various suspects who had been identified over the years. Time and again, she asked the state to line up the genetic markers.

"We submitted about eight DNA profiles," Hopper told reporters. "Each one, I was certain was going to be the suspect. And every time, Dr. Moore would tell me nope, that's not the one."

The trail went cold again. And then last April, Hopper read news reports about the arrest of Joseph James DeAngelo, the suspected Golden State Killer linked to at least 13 murders and 50 rapes. Hopper learned that police had used DNA information in public genealogy databases to identify DeAngelo.

While CODIS had failed to find Hlavka's murderer, she realized that if any of the man's relatives had submitted DNA information to the public sites, they might find a link. So the Portland Police Bureau sent the crime-scene DNA to Parabon NanoLabs, a Reston-based firm.

In October 2018, they found a match. Hopper had never seen McFadden's name in all the voluminous police files. She soon learned that the man nicknamed "Animal" was among Texas's most infamous killers.

Born in 1948, McFadden - a heavyset man with a thoroughly tattooed torso - was convicted of two counts of rape in Texas in 1972 and sentenced to 15 years in prison, according to a timeline produced by the Portland police.

But just six years later, he was paroled. Then, on June 22, 1979, one month before Hlavka's death, he kidnapped and sexually assaulted another Texas woman. In October 1979, he was arrested for violating his parole and later sentenced to a life term, but again paroled early in 1985.

McFadden became a household name in the Lone Star State the next year thanks to a horrific crime and a heart-pounding escape from jail.

On May 4, 1986, McFadden kidnapped Bryan Boone, 19, Gena Turner, 20, and Suzanne Harrison, 18, from a local lake where they had gone for a night out. Harrison was found dead the next morning, sexually assaulted and strangled with her own underwear. Days later, police found Boone and Turner shot to death.

McFadden was arrested and charged in the killing spree. But then in July 1986, as he awaited trial, McFadden knocked out a sheriff's deputy and kidnapped a woman who worked as a dispatcher and jailer. He sped away, holding her at gunpoint with the deputy's .38-calibre revolver, according to a recounting of the crime spree by the Tyler Morning Telegraph, until he crashed while trying to spot a helicopter buzzing overhead.

He then held the woman hostage in a boxcar outside the rail yards for hours until she managed to flee. McFadden was eventually caught hiding at an abandoned house nearby. He was later found guilty of Harrison's death and executed in October 1999 at age 51.

But the body count left by the "Animal" apparently extended well beyond East Texas, according to the new DNA evidence uncovered in October by the genealogy lab. Hopper, the Portland detective, and her partner traveled to Texas to take more samples from McFadden's family members.

They also learned that McFadden had traveled with a woman he knew in 1979 to the Pacific Northwest - a trip that would have put him in Oregon at the time when Hlavka was murdered.

For Hlavka's family, the news is bittersweet.

"I'm very, very happy we were able to give some kind of resolution to the family," Hopper said.

"I don't think it ever goes away for them. The word 'closure' is overused, but having some answers to give them, it's a good thing."