A driver who ferried around top Sinn Fein politicians as part of their security team was a British spy, the Irish republican party admitted Friday.
Roy McShane's family said he had left Northern Ireland after being taken into "protective custody".
Sinn Fein -- the largest Catholic party in Northern Ireland and the political wing of the Irish Republican Army -- admitted McShane worked for the British intelligence services for a number of years.
Former IRA man McShane had been part of the "security team" which looked after transport arrangements for the top republicans, including Sinn Fein president Gerry Adams.
It was discovered two years ago that Sinn Fein's former head of administration was an informant, a shock revelation.
Denis Donaldson, 56, fled over the border to the Republic of Ireland and was later shot dead.
Sinn Fein said McShane had been under suspicion for some time and had nothing to fear by returning to his west Belfast home.
"He is under no threat from republicans. If he wishes to return, it is up to him to make peace with his community and in particular his family," a spokesman for the left-wing party said.
"We are not surprised by this development. The party leadership had concerns about this individual for some time over the past number of years.
"He was sidelined to the point of being removed from any work.
"The man has left his family, they have to pick up the pieces and that is a matter for him to address."
During The Troubles -- the 30 years of sectarian bloodshed between Catholics and Protestants, largely ended by the 1998 Good Friday peace accords -- informants were usually interrogated, hooded and shot.
Sinn Fein and the IRA, which has dismantled its arsenal, want Northern Ireland to leave the United Kingdom and become part of the Republic of Ireland.