One of the priests, Detective Inspector Peter Fox alleges the church protected, is Father Denis McAlinden, who he believes will go down as one of the most prolific molesters who abused dozens of children over a four-decade period.
His oldest victim was 78 before she passed away and his youngest is 28.
Father McAlinden arrived in Australia in 1949 and was transferred from parish to parish as complaints emerged about his behaviour.
"He's certainly one of the worst I've seen," Det Ins Peter Fox told The Sunday Telegraph.
In an exclusive interview, McAlinden's youngest victim, Amanda (not her real name) told of McAlindens' systematic abuse of her and her four older sisters within their own home in Adamstown during the 1990s, when he was based in their parish church, which was connected to the Catholic primary school. Amanda's mother worked as a cleaner at the parish.
Father McAlinden, who died in 2005, was accused of raping a girl in 1982, after he had been transferred out of the Maitland Diocese to a parish in WA.
He got off the charges but he was investigated again by church officials in 1985 after a complaint at the Merriwa Local School in the Hunter.
Det Insp Fox alleged the church moved McAlinden to Ireland as the net closed in.
"We met with the bishop and he apologised," Amanda said. "The bishop explained that he (Fr McAlinden) was moved on to rehabilitate him. I asked him how you rehabilitate a paedophile at a school full of children."