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4 crimes that were cracked by a lie detector test

Chris Watts answering his front door - still taken from police bodycam footage
Image Credit: Everett Collection Inc / Alamy Stock Photo | Above: Chris Watts on the day of the disappearance of his wife Shanann Watts in 2020 - ©Netflix / Courtesy Everett Collection

In Casey Anthony's Parents: The Lie Detector Test, George and Cindy Anthony agree to undergo polygraph tests to answer the lingering questions about their alleged involvement in Caylee's death. Stream now on Crime + Investigation Play.


Their findings may not usually be admissible in court, but polygraphs – also known as lie detector tests – have played a vital part in many police investigations. Here are some criminals they’ve helped to convict.

1. Chris Watts

‘There’s only one person in this room who knows what the truth is. And in about five minutes, there’s going to be two of us.’ That’s what the investigator told Chris Watts just moments before he took the polygraph test which helped unmask him as a family killer.

Watts, his pregnant wife Shanann and their two young daughters, Bella and Celeste, appeared to be the perfect, all-American family, living in a large house in the town of Frederick, Colorado. But when Shanann and the kids vanished without a trace one day in August 2018, suspicion immediately fell on Watts, who seemed incredibly calm and unbothered by the whole situation.

His unfazed demeanour wasn’t enough to fool the polygraph, which he failed. Just moments after the test, detectives sat him down and told him it was time to open up about what really happened. Watts didn’t properly confess straight away, instead claiming that Shanann had killed the kids due to their marital breakup and that he’d then killed Shanann in a rage.

The horrific truth – that he himself had murdered his whole family because he wanted to start afresh with his secret lover – was admitted much later. Watts was handed a whole life jail term.

2. Adrian Prout

Wealthy Gloucestershire couple Kate and Adrian Prout seemed to have a charming life – but things were ugly behind the scenes. In 2006, Kate wrote in her diary that her husband had thrown her against a wall during an argument, and the following year she moved out of their sprawling farm after he threatened to kill her.

Later in 2007, she demanded an £800,000 divorce settlement and vanished the very next day. Prout was arrested, and then released. Some time after, he was arrested and released again, and it seemed as if detectives would never be able to implicate him. Fortunately, the victim’s diary entries – chronicling his abusive behaviour – allowed police to charge Prout, and he was found guilty of her murder.

However, the absence of a body allowed him to stubbornly maintain his innocence – and prevented Kate’s family from getting closure. His new fiancé, Debbie Garlick, even led a national campaign to prove he hadn’t killed his wife. And, as part of this campaign, Debbie persuaded the prison authorities to allow Prout to take a polygraph.

It was a tactic that spectacularly backfired. Prout failed it so badly that he could only smile when the polygraph expert said to him, ‘You’re a murderer.’ A few months later, he confessed to the devastated Debbie that her faith in him had been misplaced, and he had indeed murdered his wife. He later pointed the police to where the body was buried, finally bringing some sense of peace to her loved ones.

3. Ryan Brunn

In December 2012, residents of an apartment complex in the outskirts of Atlanta, Georgia were told the horrific news that the body of a seven-year-old girl, Jorelys Rivera, had been found dumped in the building’s trash compactor. She had been molested and murdered.

Soon afterwards, local maintenance man Ryan Brunn was sitting in a police interrogation room, strapped to a polygraph machine. Despite being warned by the investigator that he had ‘been doing this a long time’, Brunn seemed confident, even nonchalant, saying that on a scale of 1-10, he was a ‘7.5’ on the truth-teller scale.

But his poor performance on the test made him the prime suspect in the eyes of detectives, and he was arrested the very next day. Brunn eventually confessed that he had lured Jorelys from a playground by telling her he’d found one of her rollerskates. He claimed that he had surprised himself by his actions because he ‘didn’t have, like, the intention of killing a kid’.

Brunn hanged himself in his cell just days after being sentenced to life without the possibility of parole.

4. Richard Madden

A young man named Richard Madden became a suspect when the body of 10-year-old Kami Ring was found in a field in the town of Port Deposit, Maryland. What made this suspicion particularly depressing was that Kami had looked up to Madden as a kind of surrogate uncle, and to his parents as surrogate grandparents.

She had been staying at the trailer owned by Madden’s family when she vanished late one night in June 2013, with search parties discovering her body just yards from the home. Madden had been part of the search, even posting on his Facebook page, ‘Right now, I am going out of my head... My niece, Kami is missing.’

His show of fake concern didn’t alleviate the concerns of detectives, who hauled him into an interview room and attached the polygraph sensors. His replies to questions about Kami and his actions on the night of the disappearance were blatantly deceptive, giving police enough of a reason to delve further into his activities, conduct a DNA analysis and tie him to the girl’s rape and murder.

Madden eventually pled guilty, and the prosecuting attorney secured a 67-year sentence. The number was calculated based on the average life expectancy in the region being 77, and Kami having been murdered at the age of 10, thereby depriving her of 67 years of life. ‘When he’s in prison and inmates ask why he got 67 years instead of 60 or 70,’ the prosecutor said, ‘he’ll remember why.’