Gardaí today pledged all resources would be made available to track down the killers of British spy Denis Donaldson.
Garda Chief Superintendent Terry McGinn said: “We will leave no stone unturned to bring those people to justice.”
He revealed a window was broken and the door forced open when a gunman burst in and opened fire killing Mr Donaldson, 55, with a shotgun blast in a room in the dilapidated house where he lived near the village of Glenties, Co Donegal.
Mr Donaldson, who was once head of Sinn Féin's administration in Belfast before he owned up to working for British intelligence for more than 20 years, had been warned by police that his life could be in danger after he moved into the cottage which is owned by his son-in-law Ciaran Kearney.
Mr Kearney and Mr Donaldson were among a number of people who faced charges of operating a spy ring at the heart of the then Secretary of State John Reid’s office at Stormont – allegations which led to the collapse of the Stormont Assembly nearly four years ago.
Chief Superintendent McGinn said Mr Donaldson had suffered serious injuries to his body but said she could not comment on the exact details until a post mortem examination was completed later today.
The alert was raised by a passer-by who noticed a broken window and the open door which had been forced .
The officer confirmed an extensive police investigation was under way and she appealed for witnesses to come forward.
She said: “People out there know what happened. People further away may also know something and we want them to help us with our inquiries.”
Even though unionist politicians in Belfast claim republicans were involved - despite a categorical denial by the IRA – Chief Superintendent McGinn said she was keeping an open mind as to the motive. All avenues of inquiry would be followed up, she said.
Relatives of Mr Donaldson had been staying at the isolated cottage which has no electricity or running water but Chief Superintendent McGinn confirmed today he was alone and fully clothed when he was attacked.