The Donegal Post report that Gardaí suspect someone start the fire and say they are close to finding out whom are a groups of "youths" are who were seen acting suspiciously just before the fire started:
Gardai are closing in on louts suspected of causing a €1.5 million blaze that destroyed the old Astoria ballroom in Bundoran – one of the best-known dance halls during Ireland’s showband era.
A number of people have been questioned and gardai said yesterday(Tues) that they are “following a definite line if inquiry.”
Two firemen, Damon Fergus and Tommy Hourihan, were treated in hospital for minor burns suffered while fighting flames which leaped more than 30 feet into the air.
Fireman from Bundoran, Ballyshannon, Donegal town and Belleek took several hours to bring the blaze under control. Flames re-ignited in the smouldering and had to be damped down again on Sunday evening. Garda forensic experts have examined the scene.