Dublin's Catholic archdiocese did not report child abuse allegations against former priest Tony Walsh to the Garda until 17 years after it first received a complaint.
During that period, Walsh was likely to have abused "hundreds of children", according to a chapter of the Murphy report published for the first time yesterday.
The report also reveals how a decision by an Irish church tribunal to remove Walsh from the priesthood in 1993 was overturned by the Vatican on appeal.
During this appeals process Walsh abused another child, which led to his being jailed for the first time.
In an observation, also published for the first time yesterday, the Murphy commission said "a major factor" in Rome's decision to commute Walsh's dismissal "appears to have been the lack of the imputability by reason of paedophilia".
The commission found it "a matter of grave concern that, under canon law, a serial child sexual abuser might receive more favourable treatment from the Archdiocese or from Rome by reason of the fact that he was diagnosed as a paedophile", and as such subject to "urges" beyond his control.
The Archbishop of Dublin Diarmuid Martin said last night he did not think "that was a reflection of what canon lawyers think [now]". In the case of ongoing trials in Dublin, paedophilia "was never offered as a defence".
He added, however, in the past "most of the Irish bishops felt that dealing with the Congregation for Clergy was disastrous".
Whereas the laicisation of Tony Walsh by Dublin might have been "appropriate as an exemplary sentence", he was "not sure laicisation is always the best way", he continued. It meant, for instance, that "over the years I had no control over Tony Walsh".
Archbishop Martin, who earlier issued an apology to Walsh's victims, said that "it was an appalling thing that Walsh was allowed continue for so long."
The publication yesterday of chapter 19 of the Murphy report followed the imprisonment of Walsh on December 6th for abusing three boys in the 1970s and 1980s. He was sentenced to 16 years, four of which were suspended.
While the first complaint against Walsh was made in 1978, gardaí were first contacted about him in 1991 when a boy's mother made a complaint. The then chancellor of the Dublin archdiocese Msgr Alex Stenson rang the relevant Garda station seeking details. Asked by a garda whether Walsh had a record, Msgr Stenson "evaded" the question, according to his own notes.
The commission acknowledged that Cardinal Desmond Connell "did act decisively once he became Archbishop" in 1988 where Walsh was concerned.
It was Cardinal Connell who decided to have Walsh laicised "and he pursued this course in spite of the advice and, indeed, interference of his judicial vicar (Msgr Gerard Sheehy) and in spite of the Roman Rota (Appeal Court)".
The commission also found it "unacceptable" that two gardaí who had concerns about Walsh in 1990 and 1992 "failed to pursue a thorough criminal investigation". A criminal investigation "of sorts" got under way in 1991 but "was effectively shelved because the Church was carrying out its own penal process", it said. The archdiocese finally contacted the Garda over complaints about Walsh in May 1995.