Clement Leneghan, the youngest brother of former president Mary McAleese, has called for an independent inquiry into allegations of sexual abuse at St Colman's College Newry Co Down.
In a statement early Tuesday, Mr Leneghan called on Northern Secretary Karen Bradley "to lose no time in initiating an independent inquiry into child sexual abuse at St Colman's College".
He said that while Fr Malachy Finnegan, who was president at St Colman's until 1987 and died in 2002 could "no longer be called to account in the courts, I know that other adults – both in St Colman's and more broadly within the Dromore diocese – knew of his activities and failed to act".
He said: “Gentlemen, you know who you are. On behalf of all victims of abuse, of whatever form, I call on you now to come forward and tell what you know to the PSNI. Please, do it today.
“If you can find the courage to speak then you may, even now, help bring some healing to those who continue to suffer for the crimes of Malachy Finnegan. If you choose to continue in your silence, history will not be kind to your memory.”
Mr Leneghan, who was a pupil at St Colman's from 1980 to 1987, wrote to the Belfast Telegraph last month about his experience of physical abuse there and described the school president at the time, Fr Finnegan, as a sadist.
On Monday Ms McAleese told RTÉ's Today with Sean O'Rourke her youngest brother had only recently revealed to the family, at the age of 49, that he was abused by Fr Finnegan.
Ms McAleese, who became upset as she spoke on the topic, said her brother had been "seriously, physically, sadistically" abused, and that her 90-year old mother had only learned of the abuse by reading his letter in the Belfast Telegraph three weeks ago.
Four of her five brothers had attended the school.
Noting how "my sister Mary McAleese referred to instances of abuse by Malachy Finnegan at St Colman's College Newry, " Mr Leneghan said that, for himself, "while it is true that I suffered psychological and physical abuse at that school, I will be making no further comment on the details at this time".
He did not wish, he said, that his story would “take the spotlight away from where it belongs – which is on the need for truth and justice for the many victims of Finnegan’s lifetime of criminal sexual abuse of children.”