Mark Ray Haydon was the only Snowtown offender not to be convicted of any murders, but was sentenced to 25 years in prison.
Here is a look at his involvement in covering up one of Australia's most infamous serial killings.
Who is Mark Ray Haydon?
Haydon was an associate of Snowtown killer John Bunting.
According to his Supreme Court sentencing hearing, they met at a welding course in 1989, and then worked together building shipping containers.
Haydon was married to Elizabeth, who was the sister of Bunting's partner.
During his sentencing hearings it was revealed that Haydon had a difficult upbringing.
The court heard as a toddler he was beaten by his mother, who was mentally unwell, for trivial reasons, or sometimes no reason at all.
With no support from his father, Haydon was left to cope alone and withdrew into himself. That carried into school life, where he was bullied for years.
"You were scared to ask questions, so much so that you were even too frightened to ask to go to the toilet," Justice John Sulan said when he sentenced Haydon, noting he still managed to get good grades.
"Your upbringing goes some way to explaining your passive conduct and failure to act positively once you became aware of Bunting, Wagner and Vlassakis's evil acts," Justice Sulan said.
Haydon became emotionally numb as a teenager when the older brother he idolised was killed in a car accident.
He was 39 when he was asked by Bunting to help scare Troy Youde, James Vlassakis's half-brother.
Vlassakis had made an allegation that he was sexually abused by Mr Youde when he was younger.
What was Haydon's involvement?
Justice Sulan found that Haydon did not know six people had already been murdered when he was asked to help scare Mr Youde in August 1998.
At first, he joined the attack on the sleeping 21-year-old, but when the violence escalated, he fled to another room.
"The house at Murray Bridge was very small. You must have been aware that a very serious assault upon Youde was taking place," Justice Sulan said.
"You must have been aware, from Youde's cries of pain, that he was being brutally assaulted. You did nothing. You remained in the lounge room, you did not choose to leave."
Haydon helped clean up and carry Mr Youde's body to the back shed.
The judge accepted it was the only murder for which he was present.
What happened next?
One month after, Fred Brooks, the teenage son of Bunting's partner was last seen leaving Haydon's home in Smithfield Plains, north-east of Adelaide.
Like Troy Youde, Fred Brooks was also murdered in Murray Bridge.
Haydon agreed to store the 17-year-old's body for the killers in the service pit in his shed.
He also hid the bodies of victims murdered up to a year earlier, although Justice Sulan accepted that Haydon did not know about the murders until the barrels containing their bodies arrived at his home.
"Eventually you were told that the barrels contained bodies. You were not aware of the identity of some of those who had been placed in the barrels," he said.
"Nevertheless, you continued to permit the bodies to be stored at your home, well knowing that by so doing you were protecting and concealing that Bunting and Wagner were serial killers."
In October 1998, the three killers tortured and murdered Gary O'Dwyer — a neighbour from Murray Bridge with physical and intellectual disabilities who was targeted for no apparent reason.
Haydon was not there and did not know O'Dwyer, but helped move the barrel containing his body.
What happened to Elizabeth Haydon?
A month later, in November 1998, Bunting and Wagner turned on Haydon's wife, Elizabeth, after arranging for Haydon to go to Reynella — a two-hour round trip to the south.
"By the time that your wife disappeared, you knew that Bunting was a serial killer. You were knowingly storing bodies for him," Justice Sulan said.
"I do not accept your counsel's submission that you first knew that your wife had been murdered after the barrels had been moved into the bank premises."
Instead, the judge said Haydon learned about it when he made a phone call on the drive home from Reynella.
"From that time on, you joined in deceiving others about her disappearance," Justice Sulan said.
"You lied to and deceived others, including her children, about what had happened to her."
That included lying to Bunting's partner, whose sister and son were both murdered.
"She was very concerned about the disappearance of her son and asked both you and Bunting about that," the judge said.
"Bunting told a number of lies to [Bunting's partner], suggesting that Brooks had voluntarily left home and that he had chosen to cut himself off from his mother.
"This was extremely distressing to [her]. You knew that Bunting was lying to her, you did nothing to alleviate her distress."
When police began investigating his wife's disappearance, Haydon helped move the barrels to a number of locations, eventually co-signing the lease on the Snowtown bank vault, where the truth would finally be uncovered.
What was Haydon charged with?
He went on trial charged with murdering his wife, Elizabeth Haydon, and another victim, Troy Youde, and with assisting the killers cover up six other murders.
The jury convicted him of five counts of assisting an offender, but they could not agree on the murder charges, and instead he pleaded guilty to assisting an offender in those cases too.
Why was he sentenced to 25 years?
Haydon received a 25-year sentence, believed to be the longest custodial sentence for assisting an offender in South Australian history, and longer than many served by convicted murderers.
"The court must make it clear that conduct of this kind, which I hope will never occur again in South Australia, must be treated in the most severe manner," Justice Sulan said when he handed down the sentence in 2006.
Justice Sulan said the term took into account Haydon's prospects of rehabilitation, balancing that with his crimes.
"The course of conduct you embarked upon and continued upon in the most horrific circumstances must result in a long sentence of imprisonment," he said.
In his sentencing, Justice Sulan accepted that unlike his co-offenders, Haydon had not profited from the social security fraud the others were committing.
Haydon had been behind bars for almost seven years by then, his five-month trial delayed until the ringleaders were tried and convicted.
The sentence was backdated to Haydon's arrest on May 21, 1999, with the sentence set to be served by May, 2024.
Is Haydon remorseful?
The Chair of the Parole Board Frances Nelson KC said Haydon had done well in rehabilitation, but an initial application for parole in 2017 was refused.
"He had been in prison for a very long time and we considered that he needed further resocialisation to minimise any risk he might present to the community," Ms Nelson said.
Haydon applied again in 2021, and Ms Nelson said the board had been monitoring his progress since then 'to ensure that any behavioural change is not short-term and that he's been able to maintain it'.
"His institutional behaviour has been very good, he's been easily managed, he hasn't presented problems," Ms Nelson said.
"His work in prison appears to have been well carried out.
"He certainly has done any program offered to him by way of intervention."
Ms Nelson said he had also demonstrated contrition and remorse.
"He's expressed that within the institution and anyone who's worked with him. He's certainly expressed it to the parole board," she said.
When asked if he had reached out to the families of the victims, she said 'not all victims would want to receive a letter'.
"You've got to be conscious of victims' feelings. I imagine that Haydon would do that, but I'm not sure that it would be appropriate from the victims' point of view," she said.