In the mid-80s Quevillon was said to have approached police with what might have been some useful information about the killings.
According to one unverified narrative, police were forced to discontinue their interviews with Quevillon on the orders of mental health authorities.
Another version has it that police released him because they did not consider him credible.
This has led to considerable frustration among the families of the victims, who would like to talk to Quevillon on their own but are unable to locate him because if anybody knows, they aren't allowed to tell.
This week, one witness came forth to say that Quevillon lived in Point St. Charles in the early 80s, where he was a regular at the Chez Moma depanneur on Centre street, reinforcing the possibility that he was an important witness to the crimes.
The parents of young Denis Roux Bergevin, who was was murdered at age five in Cote St. Paul in June 1985, recently held a press conference in which they complained of a lack of communication with police in the investigation into their son's premature death.
The child's body was later found in the woods in Brossard. He had been sexually abused before being hit on the head and killed. Police said a grey Chevrolet might have been involved but nothing came of the investigation.
If indeed Quevillon is still alive - he'd be about 74 if he's still alive - and truly had a history of mental illness there's a good possibility that he might be in a place such as the Pinel Institute, where many patients never leave. But it's also possible Quevillon is none of the above and that this narrative is a mutation of the truth bred through decades of desperation. Any and all solid information would be welcome.