CHURCH officials now believe that a religious fanatic stole the 800-year-old heart of Dublin's patron saint Laurence O' Toole.
The Dean of Christ Church Cathedral, Dermot Dunne, believes that the culprit hid in the building to take the 12th century preserved heart.
It was stolen from a small heart-shaped wooden box sealed in an iron-barred case.
The priceless relic was noticed missing after the cathedral opened at 9.30am on Saturday.
"Somebody must have hid in the cathedral overnight on Friday and slipped out first thing on Saturday morning. There was no sign of forced entry and all our doors are alarmed.
"If anybody went in or out it would set off the alarm immediately and the alarm didn't go off," Mr Dunne said.
He added: "The cage is pretty robust; it would take a lot to cut the metal but somehow they managed to do it."
He said "there are various speculations as to a motive. Was it a religious fanatic who is into collecting relics?
"One theory is that they are being stolen to order. Perhaps a religious fanatic wants the relic and paid somebody to steal it. Nobody has ever attempted to steal the heart in the past; it was just there and it never crossed my mind that it might be stolen.
"It has no monetary value but we have loads of silver. It's the last thing we thought would be stolen."
St Laurence O'Toole was the second Archbishop of Dublin and is the patron saint of the city.
He founded Christ Church Cathedral in the 12th century with Richard "Strongbow" de Clare.
While travelling to Rome on a pilgrimage, he died in Eu, northern France. His body was buried in Normandy but his heart was returned to Ireland.
"His heart was our link with the past. It's an artefact, a relic and has particular meaning to Christ Church."
Gardai who recovered the precious relics of the True Cross of Christ, which were stolen from Holycross Abbey in Co Tipperary last October, have been assigned to the case.
Dean Dunne added: "I am appealing to whoever did this to hand it back; it's a desecration of a holy place. I'll take it back without any questions asked; we just want it back."