Thomas was originally arrested for the double murder in 1970. He was found guilty by two juries despite a strong alibi. Thomas was then pardoned in 1979 and a Royal Commission of Inquiry found that key evidence had been fabricated by the police.
Author Ian Wishart's new book, Arthur Allan Thomas: The Inside Story, claims that Det Sgt Len Johnston did more than plant evidence. He writes that Johnston was responsible for killing the Crewes and framing Thomas.
Thomas told TV ONE's Breakfast today that he had never before considered Johnston as the killer, believing that the culprit was most likely Len Demler, Jeanette's father.
But Wishart said his investigations brought to light new evidence that led him to focus on Johnston.
"Everywhere we went, Len Johnson kept on turning up in this case... as the person planting all of the key evidence...(fabricating) the case against Arthur Thomas."
Wishart said that Johnston's motive may have stemmed from blackmail over a burglary and insurance fraud.
The Police Association has dismissed the claims. Spokesman Greg O'Connor described Wishart's book as "scurrilous rubbish".
But Thomas is backing Wishart's theory.
"I'm not surprised, the police were corrupt to the highest degree in my case."
Thomas said that even now people struggle to accept his innocence. He said he has been let down by the police, the courts and the justice system.
"I had great faith in the police in the early days... I had nothing to hide. I helped the police where I could and they let me down," he said.
Back in July, Thomas' ex-wife, Vivien, spoke out about the murder mystery. She sent a letter to Justice Minister Simon Power, requesting he re-open the cold case.
Now known as Vivien Harrison, she was accused by police of being involved in the double homicide by feeding the Crewes' baby.
While a statement from a local farmhand led to her being cleared of any involvement, the case did lead to the demise of her marriage and force her from the country.
Vivien filed for divorce after Thomas' guilty verdict remained in place after the second trial. The pair never spoke again, but she remained a staunch supporter of his innocence, maintaining he was home with her at the time of the murders.