A 74-year-old man has appeared before the Special Criminal Court charged in connection with the murder of Denis Donaldson ten years ago.
Patrick Gillespie, with an address at Craigvar Street, Glasgow, Scotland was charged with withholding information regarding the involvement of another person in the killing of Donaldson.
Donaldson, a senior Sinn Féin official, was shot dead at an isolated cottage near Glenties in Co Donegal in April 2006.
The 55-year-old had been living there since his exposure as an MI5 agent the previous year.
The Real IRA claimed responsibility for the murder in 2008 but the circumstances surrounding Donaldson's outing as a British agent and subsequent murder have long been shrouded in mystery.
A long-delayed inquest into the shooting has been adjourned almost 20 times.
Gardaí have repeatedly urged the coroner to postpone the inquiry, citing concerns it might compromise their criminal investigation.
The delays have been a source of anger for Donaldson's relatives who have launched a legal action against the State as a consequence.
In 2014, gardaí made a mutual assistance request to a police force outside the Republic in a bid to gain what it described as potentially "significant" evidential material.
That material was secured in March this year.
Two men were arrested in Donegal on Tuesday as part of the investigation into the murder.
The second man, who is in his 40, has been released without charge.
A file is being prepared for the Director of Public Prosecutions.