FAILINGS that allowed notorious paedophile priest Brendan Smyth to abuse children for four decades will today be examined by a public inquiry.
Northern Ireland's long-running Historical Abuse Inquiry (HIA) is holding a focused module into how Smyth got away with his crimes for so long.
The serial child molester frequented Catholic residential homes and was convicted of more than 100 child abuse charges.
Retired judge Sir Anthony Hart is leading the HIA inquiry, one of the UK's largest inquiries into physical, sexual and emotional harm to children at homes run by the church, state and voluntary organisations.
Smyth, who was at the centre of one of the first clerical child sex abuse scandals to rock the Catholic Church in Ireland, was eventually convicted of more than 100 child abuse charges on both sides of the Irish border over a 40-year period.
Despite allegations being previously investigated by church officials, including the former Irish primate, Cardinal Sean Brady, as far back as 1975, it was almost 20 years before he was jailed.
Instead the cleric, a member of the Norbertine order, was moved between parishes, dioceses and even countries where he preyed on victims who were as young as eight.
He died in prison in 1997 following a heart attack.
The HIA inquiry is being heard at Banbridge Courthouse, Co Down.
Smyth's abuse has already been described by a number of witnesses who have previously given evidence to the inquiry.
This week's module will therefore concentrate on an examination of what opportunities there were to prevent Smyth carrying out the abuse of children and the inquiry panel will consider whether any action, or inaction, amounted to systemic failings.
The module is expected to last for a week. Cardinal Brady is among the witnesses set to give evidence.
The inquiry was formally established in January 2013 by the Northern Ireland Executive.