But a new revelation by the single mother’s son, Adam James, may provide a new lead.
Stating in 2013, that he had been abused by local priest, Father Anthony Bongiorno, in the month leading up to his mother’s murder, Adam, who was 11-years-old at the time, has now told the ABC that he was also sexually assaulted on one occasion by a second priest, Father Thomas O’Keeffe.
The two priests both lived and worked at St Mary’s Parish in Thornbury – a stone throw from Maria James’ bookshop.
Following the abuse, 11-year-old Adam informed his mother, understanding that she would confront Father Bongiorno.
Bongiorno was later seen covered in blood; on his face, arm and hands around the time of Maria's murder.
But in 2015, police ruled out Father Bongiorno as a suspect, with no explanation made public, however, sources close to the investigation have disclosed to the ABC that Bongiorno’s DNA did not pair with that found at the scene.
Despite this, O’Keeffe, who passed away in 1984 has never been named a suspect by police – prompting Adam and his older brother Mark to call for police to launch an official investigation.
Mark, now 50, revealed in the ABC's new podcast TRACE that he still remembers his mother turning from the stove on the morning of her murder and saying, “if anything happens to me, make sure that Adam is looked after.”
It is now known that O’Keeffe had a history of violence and sexual abuse, before assuming his role at St Mary’s in 1978. He allegedly preyed on young children while at the Doveton Parish in south-east Melbourne, within a ring of other paedophile priests.
Keeping a far lower profile in comparison to his colleague, Father Bongiorno, Mark James told the ABC that he remembers O’Keeffe as “the cold silent one in the background."
"I was actually scared of him as a young boy,” he recalls.
TRACE has since interviewed several other victims of Father O’Keeffe.
One of which, being James Shanahan - who at 11 years-old was abused for three years by O’Keeffe at East St Kilda’s Christian Brothers College.
"O'Keeffe came to my classroom and took me out of it for the purpose of sex education," Mr Shanahan told the ABC.
"We went into the brothers' residential quarters, into a very large room, and he started to fondle me."
"At that point, I remember disassociating almost straight away. I remember looking out the window, so very bright sunlight, and I just focused on that and that's mentally where I went."
Despite attempting to detach himself, Shanahan recalls O’Keeffe binding his wrists with cord or rope and later threatening him with a knife within his own home.
"He raped me and threatened to run me through with this carving knife. He was out of his mind with rage."
In a 1999 submission to the Catholic Archdiocese of Melbourne, Shanahan described the abuse as violent, sexual, ritualistic and sadistic. He also says he witnessed murders at cult-like gatherings.
After meeting with Shanahan in 2000, the Church-appointed Independent Commissioner, Peter O’Callaghan QC, stated in his formal response: “I am satisfied that Mr Shanahan was a victim of sexual abuse inter alia by Father Thomas O'Keefe (deceased) substantially in the circumstances described by Mr Shanahan."
"I confirm that the events which Mr Shanahan describes are extraordinary, but I have no reason or justification for doubting his credibility."
Now 67, Shanahan describes O’Keeffe to TRACE as being a “psychopath” continuing, "a friend of mine used to call him creeping Jesus, because he would sneak around - he'd love coming up behind you."
"He'd walk into the family home and he'd scare my mother because she'd be in the kitchen at the sink and he'd be standing there behind her. He'd walked in and hadn't made a sound."
Episode four of TRACE - released next week - will continue to explore Maria James' murder.