As James Robinson prepares to spend the rest of his life behind bars, it was disclosed a further three victims have come forward.
Detectives say the three men reported their abuse at the hands of Robinson during their investigations, but declined to take part in the court process.
The number of lives irrevocably changed by Robinson's evil now stands at nine, but detectives say they are certain more are remaining silent.
Today they are urging these people to take the brave step to talk to police.
Commenting after the guilty verdicts, Detective Sergeant Harry May said: "As we investigated this case, we found nine victims. Six were mentioned in court and for personal reasons, three weren't able to come to court.
"I have no doubt there are more victims, not only in this country but in America.
"On a personal note, I would like to say how brave these men have been, giving their testimonies in court.
"We couldn't have done it without them."
Detective Chief Inspector Steve Bimson, who headed the Major Investigation Team, spoke of the difficulties of bringing Robinson to justice
He said: "Historic abuse cases are always difficult. We rely very much on witness testimony, which in many cases is many years old and clearly we have problems with fading memories.
"In this investigation, the first complaint was made in 1985. As the investigation started, Robinson moved to the States and legalities, at that time, stopped us from bringing him back.
"Over the following years there were many letters from the church to Robinson, asking him to come back, but clearly Robinson didn't want to return to the UK."
Mr Bimson added: "Whilst Robinson wasn't seen as a sexual predator at the time, going through the grooming that took place - it was the same process - he became ingrained in these families, he became a trusted member of the family, so he could target these individuals.
"But it wasn't recognised at the time that this was taking place.
"Looking at Robinson now, his abusive activity started in the late 1950s. He became a trusted member of the community and he then built on that by joining the priesthood.
"We have heard evidence from people who thought he was a fine priest who would come into a parish and make changes and start motivating people.
"They found it difficult to believe he had committed this abuse.
"But clearly the evidence and the decision of the jury by accepting what the victims have said, demonstrates this abuse has taken place and Robinson did live this double life.
"We know there were other victims who didn't want to be part of the process. I'm sure as the publicity of what we are doing now there will be others.
"If anyone does want to get in touch with us, they will be dealt with sensitively and confidentially."