Bradley Murdoch is among a long list of notorious murderers never to admit to their heinous crimes, denying families the closure of fully knowing what became of their loved ones.
In newly released footage taken weeks before Murdoch's death on July 15 last year, the convicted killer claims to have no knowledge of the whereabouts of victim Peter Falconio's body or his 2001 murder.
Murdoch was convicted of killing Mr Falconio in 2005 but maintained his innocence despite several failed appeals and continued pressure from police for information.
Denial is a not an uncommon response by the criminally minded, with many including notorious backpacker killer Ivan Milat also taking secrets to the grave, Central Queensland University criminologist, Xanthe Mallett explained.
"A lot of these crimes are about power and control and dominance, so it's a way of maintaining that power and keeping people interested in them," Dr Mallett said.
"If you give up the body, for example, then people are going to stop showing interest in you because you have no cards to play.
"So they tend to keep those secrets because then people will keep coming back to them, and they feel important. They love the infamy of it."
In the video, Murdoch aggressively denies knowing the whereabouts of Mr Falconio's body, and appears to become angry and frustrated with the questions.
"I know nothing. I've said this for 22 years. I know nothing," an increasingly vehement Murdoch tells the officers.
"I've said the same story over and over and over, and now you're here at the last minute because I'm f***ing dying."
Practiced liars can appear convincing in their responses because they have learned how to mimic genuine emotions, Dr Mallett said.
"They're very good at manipulating people and mimicking responses like outrage.
"He's been doing this for 25 years, and he's a psychopath so he is a good liar."
Ms Lees and Mr Falconio were travelling a stretch of the Northern Territory's remote Sturt Highway when they encountered Murdoch.
After directing the couple to pull to the side of the road, indicating their van may have an issue, Murdoch shot Falconio and cable-tied Ms Lees, placing a cover over her head.
Managing to break free of her bonds, Ms Lees escaped and hid in bushland for hours while Murdoch tried in vain to relocate her, with the then 27 years-old managing to flag down a passing truck.
