DNA evidence reveals family man in Australia was teenage killer who escaped Nebraska jail

William Leslie Arnold was just 16 years old in 1958 when he killed his parents and buried them in the backyard after they refused to let him borrow the family car to take his girlfriend to a drive-in movie showing of The Undead.

Arnold went about his life in and around Omaha, Nebraska, telling everyone – even family members – that his parents had taken a trip. Two weeks later he was arrested, confessed to the killings and led investigators to his parents’ makeshift gravesite.

The following year he was sentenced to two life sentences in the Nebraska state penitentiary. And that – most people expected – should have been that.

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But by the time Arnold died in 2010 in Brisbane, Australia, his life had taken a series of very unexpected turns. For one, he’d escaped prison in 1967, in what the prison warden said was one of the “cleanest” escapes in his experience, and then gone on the run for half a century.

Last week, the US Marshals Service announced that he died, aged 67, not as William Arnold but under the alias of John Vincent Damon. Between his escape – with another prisoner, James Harding, using masks used to fool guards who conducted daily head counts at the prison – and his death, he’d lived as much-loved family man, marrying twice and fathering two children.

Immediately after the escape, the pair travelled by bus to Chicago where they split up. Harding was captured within a year but Arnold vanished. He married within three months and became a father, moved to Miami and to California, divorced, then moved to New Zealand in 1978 and finally to Australia, where he worked as a salesman.

The FBI worked on Arnold’s case into the 1990s, then handed it back to the Nebraska department of corrections who passed it over the US Marshals Service. And there his case stayed, gathering dust, until Geoff Britton, chief of the office of law enforcement support in California, set his mind to solving it.

When Britton started working on it, Arnold had been on the run for more than three decades. Britton became obsessed and worked the case for nine years from 2004 to 2013 at the state of Nebraska department of correctional services.

“To kill your parents over the use of the car to go to the movies – that’s not normal. It made me wonder if something else was going on,” he told CNN last week.

In 2020, the case was handed over to Matthew Westover, a deputy marshal in Nebraska. “One of the guys left the office, and [when you leave] you have to hand over your cases. So one of my buddies gave me this case, as kind of a joke, you know, like ‘you’re never going to find this guy,’” Westover told CNN.

The deputy read up on the case, in particular “The Mystery of Leslie Arnold”, published in the Omaha World-Herald by reporter Henry Cordes in 2017. Cordes had portrayed Arnold sympathetically – as a good student who had a difficult relationship with his parents and shot them after an argument with his mother over his girlfriend.

For the eight years Arnold was in prison he’d been a model inmate, a dedicated musician who could have qualified for early release. With some irony, the men’s escape was made through the window of the prison music room, and over a 12ft fence using a T-shirt slung over it to protect them from razor wire.

“From day one, I was hooked,” Westover told the network.

The marshal drove five hours to see to James Arnold, Arnold’s younger brother who gave a DNA sample that Westover referenced across an ancestry site. Nothing came up for two years until he received an alert of a match and an email from a man in Chicago who said he was looking for his biological father.

The man has asked not to be identified, but he told the investigators he knew his father as John Damon, and Damon had told him he was an orphan. The man asked who his father was and why he’d been in prison. “So I had to tell him,” Westover said. “I told him, ‘Well, he was an orphan. He didn’t lie about that, but he killed his parents, that’s why he was an orphan.’”

Arnold’s son told CNN: “There’s no warning label on the DNA test kit telling you that you might not like what you find,” he said. “But I don’t regret doing it, and I’m glad I now know the truth about my dad.”

According to CeCe Moore, genetic genealogist at Parabon Nanolabs, the case is unusual in the sense that law enforcement, who may be unable to find a match in small, government-linked databases including the national DNA index, are not usually able to access large, commercial genealogy services.

“It’s an unusual story only because it’s one of the first that used this approach successfully, but it’s not unique,” she said. “It’s always interesting to hear the other side of the story – what does somebody who escapes from prison do with the rest of their life?”

The big three commercial genealogy databases – AncestryDNA, 23andMe and MyHeritage – do not permit law enforcement to put crime scene or unidentified remains DNA into their system under their terms of service. But if a family member – in this case Arnold’s brother – permits it, a search run through the 40m DNA signatures in the commercial database can return a “hit” in hours. US marshals have not said which database they used.

“What makes this case unique is they’re using a living person’s DNA to fish for this escapee or his family through shared DNA,” Moore said. “There was nothing to stop them using the large databases because the younger brother was willing to put his DNA in the databases and allowing law enforcement to access them.”

Moore said her company’s job tracking missing people would be made easier if the commercial services relaxed their restrictions. “For the jobs I do, which is identifying murderers and rapists, and Jane and John Does, we would be able to work more efficiently. At the moment, these cases can take years to solve.”

The approach the Marshal Service used to track Arnold could now, in theory, be used to track dozens of unsolved mysteries, including the men who escaped from Alcatraz – assuming they survived the swim across San Francisco Bay and fathered children – or the missing hijacker known as DB Cooper.

“Some may never have had children but there’s always going to be a certain percentage that did and eventually a number of the cases will be solved,” said Moore.

Still, the fascinating story of William Leslie Arnold has its own twist. Britton told CNN he thinks the escapee “became the parent who he wanted to be, or the one he wished he had”. Arnold’s son concurs: “Although it’s shocking to know that his life began with a terrible crime, his legacy is so much more than that.”

• This article was amended on 14 May 2023 to correct the year when the murders took place. It was in 1958, not 1957.