I confess..Denis Donaldson reveals he was a spy for Special Branch and MI5 flanked by Martin McGuinness and Gerry Adams

GARDA detectives have arrested a man over the murder of former Sinn Féin official and republican MI5 agent Denis Donaldson.

Mr Donaldson was blasted to death in April 2006 at his remote Donegal cottage.

A man in his 40s is currently being held at Letterkenny Garda Station in Donegal.

He was arrested at Cloghercor in Doochary, Co Donegal, on Thursday.

The arrest was made in the same area where Mr Donaldson live.

He was assassinated four months after he outed himself as an agent who worked for the police and MI5 for over 20 years betraying secrets and strategies of both Sinn Fein and the IRA to his handlers.

He was regarded as a major figure in helping to forge Sinn Fein’s rise in politics.

Last month, 74-year-old Patrick Gillespie, a native of Glasgow but has been living in Doengal, face the Special Criminal Court in Dublin charged with withholding information about the murder of the 55-year-old.

The Real IRA later claimed responsibility for murdering Mr Donaldson.