A major investigation has revealed that the Vatican formally removed former Bishop of Galway Eamonn Casey from public ministry in 2007 after receiving multiple child sexual abuse allegations against him. 

"Bishop Casey's Buried Secrets", a major RTÉ investigation conducted in association with the Mail on Sunday, will air on RTÉ One at 9:35 pm EST on Monday night. 

The documentary will examine the Catholic Church's handling of abuse allegations against Bishop Casey, revealing that the Vatican order banning him from public ministry was never disclosed during the Bishop's life. 

The documentary will additionally investigate how the Catholic Church received at least five allegations of child sexual abuse against Bishop Casey, including a complaint from his niece Patricia Donovan. 

The Galway Diocese has stated that Bishop Martin Drennan, who was responsible for policing restrictions against members of the clergy, reprimanded Bishop Casey when the allegations came to light, according to RTÉ News. 

Bishop Casey remained a bishop until his death in March 2017 and was never convicted of any sexual crimes. He also consistently denied any allegations against him while he was alive. 

However, the new joint investigation from RTÉ and the Mail on Sunday has revealed that the Vatican formally removed him from public ministry in 2007 due to the allegations against him. 

Bishop Casey's first accuser came forward in 2001 when Casey was working as a curate in the UK Diocese of Arundel & Brighton. 

The complaint was initially filed with the Limerick Diocese in Ireland, who forwarded the complaint to Arundel & Brighton and the Vatican. 

However, Arundel & Brighton confirmed that the complaint was inexplicably lost and never reported to British police. Bishop Casey subsequently remained in active ministry for a further four years before moving back to Ireland to retire in 2006. 

At least two more allegations had been made against him at this time. The Director of Public Prosecutions decided not to prosecute Bishop Casey at the time, although church investigations into the matter continued. 

The upcoming documentary will reveal how the Vatican requested that Bishop Casey not "publicly exercise the ministry" in 2006 before "formally" reiterating the request a year later. 

"He was never reinstated...in spite of insistence from him and on his behalf," the documentary heard. 

Fr. Aidan McGrath told the documentary that restricting a member of the clergy from exercising the ministry was 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," Fr. McGrath told the documentary. 

Fr. McGrath added that he believes that a "formal document" was issued by the Vatican, stating that the Pope would have been aware of it. 

"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." 

Bishop Casey was forced to resign as Bishop of Galway in 1992 after he fathered a child with American woman Annie Murphy. 

The Vatican ordered him to leave Ireland, with Bishop Casey later becoming a missionary in South America before relocating to the UK. 

He died in March 2017 at the age of 89.