Dissident republicans are suspected of being behind a booby-trap bomb which almost killed an ex-police informant who infiltrated the Real IRA.
Former car thief Paddy Dixon, 48, had opened the front door of a house he shared with his son in Navan, Co Meath, when the improvised device exploded.
A crude detonator connected to the door set off the pipe bomb at the Beechgrove housing estate where he had been living openly for several years.
A Garda source said Dixon, originally from Blanchardstown in Dublin, was lucky to be alive.
"He was nearly killed," said the source. The device exploded at around 8.10am on Wednesday.
Dixon is thought to have leapt back when he spotted the pipe bomb and suffered shrapnel wounds, mostly to his legs and upper body.
He was taken to Our Lady of Lourdes Hospital in Drogheda, where he was being treated under armed guard. His injuries are described as superficial.
Garda technical experts and an Army bomb disposal team were called to the scene.
One of the main lines of inquiry is that Dixon was targeted by the the Real IRA over his former role as a police mole within the breakaway republican faction.
"The reality is that this was probably the work of the Real IRA, but there could be other reasons," said a Garda source.