Now in his 70s and with the gentle demeanour of a favourite grandparent, his eyes well with tears when he is asked if his false conviction and years in prison haunt him.
"I do try and forget because if I keep thinking about those terrible times my life becomes unbearable," he said.
"I try to push away these negative things in my mind about what these bastards did to me so I can lead a reasonable life."
Twice convicted of murdering Jeannette and Harvey Crewe but pardoned for the crimes in 1979, Mr Thomas was angry calls from the Crewes' daughter, Rochelle, to Police Commissioner Howard Broad for the case to be re-investigated were unsuccessful.
The case will instead be reviewed by senior police investigator Detective Superintendent Andy Lovelock, who will not be looking for new suspects.
"I'm expecting it to be another cover-up, I'm sad to say," he said.
"I used to have a lot of faith in the police but it was unbelievable what they did ... an innocent man went to prison and a little girl lost her parents and never knew why," he said.
"We need an overseas investigator to look at the case, otherwise it will be a complete waste of taxpayers' money."
Mr Thomas and Ms Crewe had never met, but Mr Thomas said he was willing to back her up if she wanted to petition Prime Minister John Key on the matter.
"... if she wants to I'll be very happy to go to Wellington with her and put the cards on the table in front of the Prime Minister.
"Somebody murdered her parents ... she deserves justice."
Mr Thomas said he never knew any of the detectives involved in the inquiry into the Crewe murders, nor did he have any reason to be on the wrong side of them as he had never broken any laws.
Until he read Ian Wishart's book Arthur Allan Thomas: The Inside Story, he considered Jeannette Crewe's father, Len Demler, the likely killer.
Wishart's book theorises Detective Len Johnston should have been a suspect.
"I thought it was a family matter, it was my opinion; but maybe I was wrong."
Mr Thomas went to Pukekawa Primary School with Mrs Crewe and is clearly animated when asked what his memories were of her.
"She was a lovely lady. I thought that she was a nice woman."
Mr Thomas said he had never met Mr Crewe.
The review of New Zealand's most enduring murder mystery has no set timeframe.
