Three men smashed Shaun Barker's kneecaps and hands, bashed him with a golf club, kept him in a fishing esky and put honey on his testicles for ants to eat.
However, a court has now found that none of the trio meant for him to die.
Mr Barker's remains were found charred and scattered in a remote area near Gympie four months after he was kidnapped from the Gold Coast.
The Brisbane Court of Appeal on Tuesday quashed William Francis Dean's murder conviction but substituted it with a manslaughter conviction after finding there was no intention to kill Mr Barker.
Dean's co-accused Stephen Armitage and Matthew Armitage previously successfully appealed their convictions, with the court quashing murder convictions but handing down a guilty verdict for manslaughter.
All three men were also previously convicted of torture, but will now be retried.
Accused of stealing $80,000 of the drug ice, Mr Barker was taken to a Gold Coast house where he was punched, hit with a golf club, wrapped in carpet and his hands duct-taped to his head on December 10, 2013.
He was later taken to the property near Gympie where he was kept in the esky.
Witnesses told the trial Mr Barker's kneecaps and bones in his hands were smashed, a finger cut off and honey put on his testicles for ants to eat while he was being held until around Christmas.
The events concerning the death involved people who dealt in or used drugs, Justice Philip Morrison says in his appeal findings.
Mr Barker was reported missing in January but it was only in April, 2014 that part of his skull and jaw bone were found, followed by bone fragments and eventually more substantial parts of his skeleton.
Some burnt bones were found in a fire pit.
Justice Morrison said Mr Barker's cause of death could not be determined and it was reasonable no one had intended to cause the death or harm.
"The evidence supported a finding that Barker was being held for the purpose of discovering where missing drugs or money were kept, the inference being that it was in the interests of all of the others to keep him alive," Justice Morrison said.
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