The Real IRA have claimed responsibility for the shooting of former senior Sinn Féin man and self-confessed British agent Denis Donalsdon who was killed in Co. Donegal in April 2006.
The claim was made to a Dublin newspaper at the weekend and is expected to be formally announced today at the 32 County Sovereignty Movement's Easter Commemoration in Derry's City Cemetery.
Admitting that the Real IRA carried out the killing at a remote cottage in the Glenties area, a Real IRA representative said all "traitors" would be targeted.
"Treachery is collaborating with the enemy, treachery is betraying your country. Let us give our one-time comrade an example. Denis Donaldson was a traitor and the leadership of the Provisional movement, under guidance from the British government, made provision for Donaldson to escape republican justice in the same manner as Freddie Scappaticci.
"It fell to the volunteers of glaigh na hireann to carry out the sentence and punishment demanded in our Army Orders and by the wider republican family. No traitor will escape justice regardless of time, rank or past actions. The republican movement has a long memory," the spokesperson said.
The group also vowed that Derry supergrass Raymond Gilmour is one of five men it plans to kill.