A preliminary inquest into the death of Denis Donaldson has been told that gardaí are considering criminal proceedings in the case.
Mr Donaldson was found murdered in a cottage in Co Donegal in April last year.
The former senior Sinn Féin member died as a result of gunshot wounds, the inquest heard. Mr Donaldson admitted in December 2005 that he had been a paid British spy for 20 years.
Superintendent Eugene McGovern told the coroner's court in Letterkenny that Mr Donaldson died in a violent fashion in suspicious circumstances.
Supt McGovern said that his death was the subject of a comprehensive and extensive garda investigation, which was still ongoing.
He requested an adjournment of the inquest on the basis that criminal proceedings are being considered in the case.
Solicitors representing Mr Donaldson's family said they had received a letter from the gardaí this month indicating that his death was still the subject of a criminal investigation.
The letter also indicated that no definitive motive for the crime had been established or suspect identified and that the file remains open.
A statement issued on behalf of the family afterwards said that during the last year and a half, their confidence in the current garda investigation was severely undermined.
As a result, they have been obliged to formally initiate complaints about the conduct of the gardaí.
It is understood the family have a number of concerns in relation to whether or not Mr Donaldson was adequately warned about any perceived threats to his life.
They are also understood to have concerns about whether the cottage in which he was living was under electronic surveillance by gardaí or British security services.
