Ireland's Justice Minister Dermot Ahern puts his hand to his mouth during a press conference at Government Buildings regarding the cover up of child abuse within the Catholic church Thursday November 26, 2009. [Agencies]

DUBLIN: Roman Catholic Church leaders in Dublin spent decades sheltering child-abusing priests from the law and most fellow clerics turned a blind eye, an investigation ordered by Ireland's government concluded Thursday.

Dublin Archbishop Diarmuid Martin, who handed over more than 60,000 previously secret church files to the three-year investigation, said he felt deep shame and sorrow for how previous archbishops presided over endemic child abuse, yet claimed afterward not to understand the gravity of their sins.

"They were wrong, and children were left to suffer."

There was a similarly shocking investigation into decades of unchecked child abuse in Irish schools, workhouses and orphanages run nationwide by 19 Catholic orders of nuns, priests and brothers.

That report in May sought to document the scale of abuse as well as the reasons why church and state authorities didn't stop it, whereas Thursday's 720-page report focused on why church leaders in the Dublin Archdiocese -- home to a quarter of Ireland's 4 million Catholics -- did not tell police about a single abuse complaint against a priest until 1995.

By then, the investigators found, successive archbishops and their senior deputies -- among them qualified lawyers -- already had compiled confidential files on more than 100 parish priests who had sexually abused children since 1940. Those files had remained locked in the Dublin archbishop's private vault.

The investigators also dug up a paper trail documenting the church's long-secret insurance policy, taken out in 1987, to cover potential lawsuits and compensation demands. Dublin church leaders publicly denied the existence of the problem for a decade afterward -- but since the mid-1990s have paid out more than euro10 million ($15 million) in settlements and legal bills.

The report cited documents showing how church officials learned about some cases only when devoutly Catholic police received complaints from children or their parents, but handed responsibility back to church leaders to sort out the problems themselves.