The Smithwick Tribunal has heard that there was a decision by the Cabinet to have the gangster Martin Cahill, known as The General, "put down".
The claim was made by former Detective Sergeant Owen Corrigan who had been asked by then head of the Garda Crime and Security Branch, Noel Conroy, to try and recover the paintings of the Beit Collection.
The paintings had been stolen by Cahill and his gang from Russborough House.
At the time he was asked to get involved in trying to negotiate the return of the paintings Mr Corrigan was on sick leave as a result of "nervous exhaustion" from his job in Dundalk Garda Station.
Today the former Detective Sergeant was asked by counsel for the Tribunal Justin Dillon about this.
He said the witness was not suffering from exhaustion but it was merely a deception as he was clearly able to work.
Counsel for Mr Corrigan objected saying there had been no suggestion his client had been involved in deception and medical evidence should be heard if the allegation is to be made.
Mr Corrigan said he had produced medical certificates when he was on sick leave.
The witness also claimed that there was a collective Cabinet decision that Cahill "had to be put down".
There was pressure from the British government over the theft of the Beit paintings.
Cahill was shot dead by the IRA in 1994.
The former detective sergeant also told the Tribunal that there has been a serious deterioration to his health due to the stress he is under as a result of the Tribunal.
Mr Corrigan was also questioned today about his kidnapping in 1995 by the IRA.
Along with another man, Francie Tiernan, he was taken from a car in the Boyne Valley Hotel in Drogheda, and held for several days.
In evidence today, Mr Corrigan denied that the abduction was as a result of owing the IRA money for drink for his pub.
The witness said he was taken and questioned because the IRA believed he was still working for the gardaí even though he had retired several years earlier.
He also said he was set up by Mr Tiernan.
Mr Corrigan told the Tribunal it had heard from several former Garda Commissioners and Assistant Commissioners and none of them had said anything about him passing information to the IRA.
RUC officers met with their garda counterparts on a very regular basis and again nothing was said during those meetings about him either.
The Tribunal is investigating claims that an IRA mole in Dundalk Garda Station passed information to the IRA which allowed them to kill Chief Supt Harry Breen and Supt Bob Buchanan just minutes after they left a meeting in Dundalk.
Former sergeants Owen Corrigan, Leo Colton and Finbarr Hickey all deny the allegation that they were the mole.
The Tribunal resumes hearings next Tuesday.