Mum believes murderer of son Josh Warneke is still out there, not man jailed for it

Josh Warneke was beaten and left to die. Photo / Channel 9

It's an Australian take on US documentary series Making a Murderer.

Ingrid Bishop doesn't know who killed her son Josh Warneke, but is sure it's not the man who is in jail for the crime.

Ms Bishop's six years of torture and turmoil begin in 2010 when her son, 21, was attacked and left to die on the side of the road after a night out in Broome in WA.

It took more than two years before police - with Ms Bishop hounding them all the way - arrested a suspect for his murder.

Then Ms Bishop watched the case against the accused Gene Gibson crumble - amid a botched investigation which relied on police interviews which were at best "unreliable", and contained a confession which a Supreme Court judge described as a "complete farce".

The murder charge was downgraded to manslaughter. Gibson pleaded guilty and was sentenced to seven-and-a-half years.

But now Ms Bishop is convinced police had the wrong man all along and 60 Minutes last night followed the mother on her fight to free Gibson.

"Gene Gibson is innocent, this is a no-brainer," she said.

Gibson has been in jail for four years and was charged two years after Josh's murder.

He confessed to the crime and said he killed Josh with a round, metal pole - but Ms Bishop said the story didn't match forensic evidence.

60 Minutes reporter Liam Bartlett said Gibson first confessed to running over Josh, but that story wasn't consistent with the young man's injuries.

Gibson then claimed to have hit Josh with a rock, but that story wasn't plausible either.

That's when he came up with the story of the metal pole, which Gibson said he took from outside a house, one that wasn't actually built at the time of Josh's murder.

Ingrid Bishop is so sure police got the wrong man she's fighting for the release of Gene Gibson, the man jailed for Josh's killing. Photo / Channel 9

A paramedic who found Josh's body, Jim McCall, also said it looked like the young apprentice was hit with an axe or machete.

When Josh's body was examined, a clump of hair was also found in one of his fists and looked as if it had been cut with a sharp object like an axe.

Bartlett reported the hair was sent off for analysis, but police didn't wait for results before charging Gibson.

To say it's a sorry saga is an understatement.

"It's a travesty for all involved - the victim's family and the poor bloke sitting behind bars," says Bartlett.

"You could write this for a Hollywood script - they'd turn it into an African American being victimised in the Mississippi. The sickening thing is, this is real life."

Gibson, is the unwitting 'star' of the story - the man who Ms Bishop no longer believes killed Josh.

"I don't know who killed my son, but I know who didn't," she says, voice dripping with disgust.

"I'm not going to have someone sit in a prison because no-one else could be bothered doing their jobs."

Bartlett reported Gibson was questioned by police over the murder for a gruelling nine hours.

His friends, who were with him at the time of Josh's murder, told police Gibson didn't kill the young man, but later changed their stories and said he did commit the crime.

They wanted to set the record straight and told 60 Minutes they lied and police pushed them to do it.

During the investigation into Josh's death, police questioned another man but did not pursue him.

That man was Aaron Sibosado, and Broome author Glenyse Ward, said he told her family he killed Josh with an object like a tomahawk.

The 60 Minutes crew confronted Sibosado and he said his confession was because "I talk a lot of bulls***".

Jailed: Gene Gibson. Photo / Channel 9

Bartlett reported Sibosado told police he was drunk when he said he killed Josh and police let him go.

"I'm furious," Josh's mother said.

"Senior investigating officer tells me 'we'll get your man'.

"But it was going to be easier to set up Gene Gibson and tick that box rather than do some real investigation work."

Gibson, who since being jailed has protested his innocence, is preparing to appeal his conviction.

In the fallout from the botched investigation, two officers faced disciplinary charges and were fined after pleading guilty, while nine other officers received managerial interventions.

Bartlett says the case is a tragic injustice doled out to a man who could not even understand the charges he was faced with.

"At the crux of it is Gene, a Western Desert Aboriginal, who was let down at every turn," says Bartlett.

"He was 20 years old. Pintubi is his native dialect and his strongest dialect, and then he speaks two other Aboriginal dialects. And in the Supreme Court they actually worked out that English was his fourth and last language.

"But he couldn't speak or understand it very well at all. So he's already cowed by figures of authority, especially police, and he's arrested and gives a so-called confession which is a complete farce. A Supreme Court judge has said that - they talked to him for hours. They didn't have an interpreter. They didn't record the interview ... it's illegal and as depressing as it is wrong."

60 Minutes contacted the West Australian police commissioner to explain the investigation into Josh's death, but declined to comment.