A senior Sinn Féin politician has said paedophile priest Fr Malachy Finegan physically abused him and tried to sexually groom him.
Conor Murphy said the priest, who died in 2002, dragged him into an office in St Colman's College, Newry, County Down, and beat him with a stick.
Mr Murphy told the Press Association that the priest asked him explicit questions, including if he loved him.
Fr Finegan taught in St Colman's from 1967 to 1976.
He was also the school's president.
He has also been accused of abuse while he was a parish priest in Clonduff, County Down.
Details of the abuse claims against Fr Finegan were revealed in a BBC Spotlight investigation in February.
Fr Finegan was never prosecuted for sexual abuse, but allegations against him were reviewed by the National Board for Safeguarding Children - a clerical abuse watchdog set up by the Catholic Church.
Mr Murphy, who was a pupil at St Colman's between 1975 and 1980, said he was angry that no one stopped the priest's abuse despite his sexual interest in young boys being common knowledge in the school.
He has demanded a full investigation.
He described the priest as a "violent, volatile, bullying drunkard" and recounted an incident from when he was a 14-year-old pupil at the school.
"There was a bit of ruckus going on in the class we were in and Finegan burst into the room," he said.
"He singled me out, he dragged me out by the hair, by the crown of your head, dragged me along the corridor, up two flights of stairs into his room and then he beat me with a stick on the hands and about the body.
"He was always prone to more violence than was perhaps to do with discipline.
"And then he suddenly flipped, as I was almost expecting, he sat me down and started asking me personal questions - did I smoke, did I drink? Bear in mind I was 14. Did I go out with girls? Did I masturbate? Did I love him? This type of conversation.
"I can't remember my responses but I wasn't shocked by the conversation, because I had been forewarned by other pupils that this was what was likely to happen."
Mr Murphy said his experience "paled into insignificance" compared to those men who have come forward to say they were sexually abused by the priest.
He said he wanted to go public with his story to reassure others they they would be believed if they wanted to break their silence.
Fr Malachy Finegan: A controversy years in the making
A priest, a teacher and a school president who died in 2002 - but it's only recently that accusations about Fr Malachy Finegan have emerged publicly.
In February, the Catholic Diocese of Dromore revealed it had reached a settlement with one of 12 people who had accused the priest of abuse while at St Colman's College.
Another victim - Sean Falloon - spoke publically of being abused for eight years from the age of 10 while Fr Finegan was a parish priest.
In the weeks since, the Catholic Church and police have come under fire for what they knew about the priest and when.
Bishop of Dromore, John McAreavey, resigned over the controversy, specifically for serving at Fr Finegan's funeral mass despite knowing of claims made against him.
A group of victims have also complained to the Police Ombudsman over claims the police were aware of the allegations against the priest in 1996 but failed to interview him.
Mr Murphy said that while he was not aware the priest was sexually abusing students at time, everyone in the school knew about the explicit conversations he would try to instigate.
"We knew it was wrong, it was inappropriate, that it was not natural for a man, particularly a priest, to behave in that fashion."
He added that "we didn't understand it was essentially a grooming exercise" but that students were aware that "if you were in a room alone with him that he was liable to ask you very inappropriate questions and display an inordinate interest in your sexual development".
"We didn't know that he had sexually abused boys but we knew and understood that he had an unhealthy interest and the way you approached that conversation was to shut down and try to get out of that office as quickly as you could."
He added: "I didn't know what a paedophile was, we didn't know what the behaviour of a paedophile was, but as an adult looking back it was fairly obvious to us that these were the classic symptoms of paedophilia."
Mr Murphy also said Fr Finegan would "assault pupils" and that it was not simply about discipline.
He added that he believed the priest was "drinking very heavily".
"I was only a kid but I had worked in a bar from when I was 12 years old and I knew.
"He would appear in the corridor in the mornings with his shoe laces undone, his vest hanging out underneath his shirt, his eyes bloodshot and quite aggressive.
"He would launch an attack if someone was coming up the corridor with their tie not straight they were liable to get thumped in the face for it.
"That was going on as a matter of course through my time there."
Mr Murphy said the Catholic Church, the school and wider education authorities all had questions to answer as to why no one intervened to stop Fr Finegan.
"They left him to abuse people without any interference probably across two generations of boys," he said.
'Gives people confidence'
"I am angry that a man who was a violent, aggressive bully, a drunkard with an unhealthy interest in children, and that was obvious, was allowed to be a principal of a school, was allowed to be teacher in a school over a long number of years, allowed access to young boys."
He said that the system of administration in St Colman's College "allowed a paedophile to flourish" and that "it needs to be investigated" as to why this happened.
Mr Murphy, who has made a statement to lawyers representing victims of Fr Finegan's abuse said he hoped his story would help to validate the accounts of others who have come forward.
"I hope me speaking publicly maybe gives some people confidence to come forward, and that's the purpose of me speaking.
"It's not to draw any degree of sympathy for myself but it's actually to encourage others and to say that we believe those who say they were sexually abused, we know the pattern in the school."
The Catholic Church has described Fr Finegan's abuse as "abhorrent" while St Colman's College has said it condemns in the "strongest possible terms the physical, sexual and emotional abuse inflicted by Malachy Finegan".
In a further statement, the board of governors at St Colman's College said: "The board unreservedly condemns all abuse and advises that anyone who is a victim to contact the PSNI.
"The school is co-operating fully with a PSNI investigation regarding historic abuse.
"This is the most suitable mechanism to address these issues. Until such investigations are complete the board will not be making further public statements."