There is no denying that republicans are angry and disgusted by the outing of the once popular, and occasionally revered, Denis Donaldson.
The typical reaction of Sinn Fein activists in Belfast was one of stunned disbelief.
Brought up in the strongly republican Short Strand area of east Belfast, the 55-year-old grew up with the IRA’s struggle.
His father was an IRA man in the 1950s and it wasn’t long before Donaldson joined himself. Sentenced to ten years in Long Kesh, and it was during this time that he met key republican figures Bobby Sands and Gerry Adams.
A smuggled photograph, picturing him arm-in-arm with Bobby Sands and others, helped to ensure his reputation in later years.
His time in Long Kesh’s Cage 16, regarded as a republican think tank, further bolstered his reputation as a committed republican and a serious thinker.
Released in 1976, Donaldson became active in the developing Sinn Fein party, with its peace strategy in its infancy at the time.
A smiling, canny man, Donaldson rose through the republican ranks in the 1980s.
Holding the trusted position of IRA intelligence officer for a lengthy period, Donaldson would have had access to the IRA’s most secret information.
It was during this time that he was recruited. His statement on Friday claims he had “compromised” himself during “a vulnerable time”, but admitted he had been paid money for his information.
By the time he flew to Lebanon in 1987 as part of a republican delegation that tried to secure the release of Irish hostage Brian Keenan, he was already working for (the then RUC) Special Branch.
Working in the background, Donaldson shunned the Sinn Fein spotlight but became increasingly involved in the political process. With a reputation as ‘a charmer’, he was already established as a key aide to Gerry Adams and the rest of the party leadership, and effectively worked as a Sinn Fein chief of staff.
As the peace process began to develop momentum in the early 1990s Donaldson was playing a key role in coordinating Sinn Fein’s offices in the United States.
He helped organise the first US trips by Gerry Adams and Martin McGuinness and was granted a visa waiver to enter the country.
It remains unclear whether the US goverment was aware of his work, which would have included spying on US citizens for the British government.
He had an invaluable listening post not only on Irish-America but also on the US administration, which was at loggerheads with the British government on many aspects of Irish policy. Donaldson met State Department officials regularly, carrying messages back and forth from the republican leadership.
Donaldson ensured his advancement by unswervingly supporting the Adams-McGuinness leadership and the party’s peace strategy. He was a key aide in the negotiation of the 1998 Good Friday Agreement.
When the Assembly was established, Donaldson was given the key job of head of Sinn Fein administration. From then until his arrest in October 2002 he was in a position to feed his handlers valuable information.
The move was seen as highly unusual as republicans had been consistently been blocked from carrying personal protection weapons.
Suspicion grew after details of the PSNI operation ‘Torsion’ claimed that documents had been removed from Donaldson’s house, photocopied and then returned. Attempts to secure official documentation on this process resulted in British officials issuing a series of ‘Public Interest Immunity Certificates’ -- censorship orders.
During the past year, with the assembly collapsed, Mr Donaldson worked at Sinn Fein’s Falls Road headquarters.
It has since emerged that just weeks before his arrest Donaldson had become the first Sinn Fein official to be granted permission by the PSNI to carry a gun for his own protection.