The former Bishop of Galway Eamonn Casey was formally removed from public ministry in 2007 by the Vatican, following "allegations" which, RTÉ has established, included his niece Patricia Donovan's complaint of child sexual abuse.
An investigation conducted by RTÉ in association with the Irish Mail on Sunday has examined the Catholic Church's handling of allegations against Bishop Casey in a documentary which will be broadcast tomorrow night.
The Vatican restriction was introduced in 2007 and never publicly disclosed until a statement to RTÉ for tomorrow’s documentary, which reveals evidence that Bishop Casey violated the Vatican’s sanctions on several occasions.
The Galway Diocese has stated that the late Bishop Martin Drennan, who was responsible for policing the restrictions, reprimanded Dr Casey when he was made aware of such breaches.
Eamonn Casey consistently denied all the allegations against him.
He was never convicted of any sexual crimes and remained a bishop until his death in March 2017.
However, the Vatican confirmed to RTÉ’s documentary unit, that Bishop Casey was formally removed from ministry in 2007, following allegations which included child sexual abuse.
Prior to his niece coming forward, Bishop Casey’s first accuser, made her allegation in 2001, when he was working as a curate in the UK Diocese of Arundel & Brighton.
The Limerick Diocese forwarded the complaint there and to the Vatican.
Arundel & Brighton has confirmed that the complaint was inexplicably lost and was not reported to the British police. As a result, Bishop Casey remained in active ministry for a further four years.
In early 2006, the Irish Bishops announced that Eamonn Casey was moving back to Ireland to retire.
However, at that stage, the Vatican had received at least two allegations of child sexual abuse against him. The DPP decided not to prosecute him at the time, but Church investigations continued.
After repeated requests for information, the Vatican confirmed to RTÉ that, by 2006, following unspecified "allegations", "Bishop Casey had been requested not to publicly exercise the ministry" and that this was "reiterated formally" a year later.
It also revealed that "He was never reinstated...in spite of insistence from him and on his behalf" and "regardless of the outcome of the civil procedures".
In the documentary Fr Aidan McGrath described restricting someone's ministry as "a serious matter".
"..and to do so in a formal way, I would read that as indicating that the Congregation for Bishops had made some kind of a ruling with regard to Bishop Casey, on the basis of complaints received, that he should not publicly exercise ministry," he said.
Fr McGrath said this led him to believe there was "a formal document", in the form of a decree.
"That would have put down the actual restrictions on his ministry and the reasons why, and that decree would have had to have been made known to the Pope, because it involved a bishop.
Safeguarding expert Ian Elliot said it would not have been a judgement reached easily.
"So, I think you can take it that was an indication that there was a belief within the Church that he had not behaved appropriately and in line with his position and his clerical duties."
The former president Mary McAleese, who is a canon lawyer, said: "We know that there were significant allegations of sexually predatory conduct and from a number of different sources."
She said there may have been "a pattern of predatory behaviour" that would have to have been taken "very seriously and earnestly".
"...because they are looking at it from the point of view of restoring him to a ministry where he would have full public access, and they may have been, and clearly were, worried about that, significantly worried about that".
When RTÉ requested clarification from Archbishop Charles Scicluna, the President of the Vatican department responsible for handling complaints of child sexual abuse, he replied: "Cases concerning Bishops are reserved to the Holy Father personally and only the Secretariat of State would be in a position to share information."
The Vatican’s Secretary of State, Cardinal Pietro Parolin, did not respond to requests for information.
The documentary, Bishop Casey’s Buried Secrets, will be broadcast tomorrow at 9.35pm on RTÉ One and will be available worldwide on the RTÉ Player.