The Smithwick Tribunal has been told that one of its most important witnesses was a member of the IRA who had passed good information to the RUC that saved lives.
However, a retired RUC officer went on to say that the man, Peter Keeley, became an 'intelligence nuisance' and he refused to sanction him as a source for the police service.
Mr Keeley, who also uses the name of 'Kevin Fulton', claims he was involved in the IRA in Dundalk and in south Armagh.
He has claimed he joined the British army, but was recruited by intelligence services and sent back to join the IRA as an agent.
He has claimed retired Detective Sergeant Owen Corrigan passed information on to the IRA and that he told the subversives there were two RUC men at a meeting in Dundalk on 20 March 1989.
Chief Supt Harry Breen and Supt Bob Buchanan were killed in an IRA ambush shortly after leaving that meeting.
Mr Corrigan has always emphatically denied the allegation. Mr Keeley has yet to give evidence to the tribunal.
Today, the tribunal heard from a retired RUC Detective Inspector who spent several years working for CID (Criminal Investigation Department) in Newry.
He gave his evidence from behind a screen to protect his identity and was identified only as 'Witness 60'. He said there was no difference in terms of security threat for police officers in the towns of Newry and Dundalk.
Asked if he knew Mr Keeley, the witness said he knew that he was a member of the IRA. He had also passed on good information to a number of organisations. On one occasion, he passed information that saved people's lives.
However, the quality of the information at a later stage deteriorated and the witness refused to authorise the continued involvement of Mr Keeley as a source.
He classed him as an intelligence nuisance. Mr Keeley was more trouble than he was worth, added the witness.
Under cross-examination by counsel for Mr Keeley, Neil Rafferty, the witness acknowledged that he believed his client was in the IRA.
It was put to him that the quality of information deteriorated after 1994 when he said Mr Keeley had been exposed as an agent. Witness 60 said he was not aware of that.
Earlier the tribunal judge, Peter Smithwick, refused a request from Freddie Scappaticci to be allowed legal representation at more of the hearings.
Mr Scappaticci denies he was the deputy head of the IRA internal security unit known as the 'Nutting Squad' and at the same time the most prized British army agent within the paramilitary organisation.
He had sought to be allowed legal representation every time the names Peter Keeley and Kevin Fulton are mentioned, as well as the former British intelligence handler, Ian Hurst, who also uses the name Martin Ingram.
The judge, however, refused his application.
