MAKING A Murderer's Steven Avery burned his pet cat to death by dousing it with oil and petrol and throwing it on a bonfire TWICE, police files reveal.
His sadistic act of animal cruelty "signposted" him as a future killer - but it was downplayed as almost an accident in the hit Netflix documentary.
The grim details - not allowed at his trial - are revealed by Michael Griesbach in his book Indefensible: The Missing Truth About Steven Avery, Teresa Halbach And Making a Murderer.
Griesbach, a former prosecutor who helped overturn Avery's wrongful sex attack conviction, is convinced he is guilty of murdering Teresa Halbach after he was freed in 2003.
And he accuses the documentary makers of deliberately leaving out key evidence to make Avery appear the victim of a second miscarriage of justice.
Griesbach said he was stunned by how the show brushed over Avery's history of vicious crimes including when he deliberately rammed a mum and baby with his car and held the mum at gunpoint.
Avery himself spoke dismissively of the cat torture, saying: "Another mistake I did... I had a bunch of friends over, and we were fooling around with the cat.
"And I don't know, they were kind of negging it on and... I tossed him over the fire... and he lit up.
"I was young a stupid and hanging around with the wrong people."
He also whinged he missed his daughter's birth because he was in custody over the horror.
'SADISTIC PERSONALITY'
Griesbach said the police report paints a very different picture, which the documentary chose to ignore.
He wrote in his book: "The police report stated that Avery took a cat, poured gas and oil on it, threw it in a bonfire, and then watched it burn until it died.
"A friend who was present told police that the cat jumped out of the fire, and Avery caught it and poured more gasoline on it before the animal died.
"Thousands of Netflix viewers would never know that Avery intentionally threw a cat in a fire and watched it burn and suffer a miserable death."
He said Avery, then aged 20, "[managed] to score two of the most common psychological signposts for potential homicidal behaviour - animal cruelty and a fascination with fire - into a single act."
Nearly 25 years later, prosecutors failed in a bid to admit details of the cat burning in Avery's trial for the slaughter of Teresa Halbach, who was burnt on a fire.
They told a court: "The jury must be allowed to consider the vicious and cold-hearted torture and death of Avery's cat" because of its "striking similarity [to the] object of Avery's torture on a bonfire.
"[His] sadistic personality... is highly relevant to whether he killed Teresa and mutilated her body after she died."
'TORTURE CHAMBER' PLANS
But the judge refused to allow the evidence, along with details of how Avery beat, strangled and threatened to kill his girlfriend after his release from jail.
The jury were also banned from hearing how Avery loved porn and extreme bondage sex, and had expressed a desire to murder women in a torture chamber, the book claims.
The judge also blocked allegations Avery groomed and raped his 17-year-old niece while threatening to burn down her family home.
Avery had spent 18 years in jail after he was wrongly convicted of a brutal sex attack on a jogger in Wisconsin, US.
He was awarded £28million in compensation - and days later was arrested for the murder of Teresa Halbach.
The Making A Murderer series suggests police were out to get him and wrongly pursued him over the murder of photographer Teresa in 2005.
Her charred bone fragments were found in a pit near Avery's salvage yard.
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In 2007 he was jailed for life along with his 16-year-old nephew Brendan Dassey, who confessed he helped his uncle rape, stab shoot and dismember the victim.
Both men's cases have been subject to lengthy appeals.
Prosecutor Ken Kratz, who wrote a bombshell book about the case called Avery, has also hit out at the Netflix show’s producers - accusing them of “shamefully” omitting key evidence and presenting a one-sided view of the case.
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