Dennis Donaldson, who headed the Sinn Fein office at Stormont, the Northern Ireland parliament, was expelled from the party, the Irish Times reported. Sinn Fein President Gerry Adams said Donaldson came clean after British police threatened to out him.
In a public statement, Donaldson apologized to his family and to his former comrades. He said he was recruited in the 1980s after he had compromised himself and that he was paid for his services.
In a bizarre twist to the story, Donaldson was arrested in 2002 in the so-called Stormontgate Affair. The Royal Ulster Constabulary raided the Sinn Fein office at Stormont and accused the party of running a spy ring.
"The so-called Stormontgate affair was a scam and a fiction," Donaldson said. "It never existed. It was created by Special Branch."
Irish Prime Minister Bertie Ahern called on the British government to explain Stormontgate, which halted the peace process in Northern Ireland.
Notable deaths of 2014 [PHOTOS]