A former senior police officer has been told to justify his claims of political interference in policing.
Outgoing Chief Constable Matt Baggott refused to be drawn at length on the allegations by retired senior detective Norman Baxter that officers faced government pressure to set republican suspects free.
Mr Baggott told yesterday's meeting of the Policing Board it was important he did not make a judgment in advance of ongoing inquiries but said Mr Baxter had been asked to account for his comments.
He said: "I have asked a deputy chief constable, who is responsible for issues of misconduct, to write to Mr Baxter asking him to give us an account of what happened, by who, when and to give us the detail behind his statement yesterday so we can make an objective assessment on that and see where we go.
"That will be done today and Mr Baxter will be asked to justify his comments."
Mr Baxter had accused Mr Baggott of "poor leadership" after the apologised in the wake of comments by a judge about "catastrophic failure" in the collapse of the criminal case against alleged Hyde Park bomber, John Downey.
Mr Baggott yesterday said his apology was appropriate.
Mr Baxter told a powerful Westminster committee on Wednesday there was "a culture within the Northern Ireland Office to ensure that republicans were not prosecuted".
He claimed Downing Street put pressure on the PSNI in 2007 to release two IRA suspects from questioning after a request from Sinn Fein president Gerry Adams.
The men were being quizzed in relation to the 1981 attempted murder of part-time UDR soldier Sammy Brush.
Mr Baxter said he was told of the request by a higher ranking officer hours after the suspects had been arrested.
Mr Adams said he had protested to the government about the arrests of the men, one of whom – Gerry McGeough – was subsequently convicted in relation to the attack.
"My protest at that time was entirely appropriate given that the British government had given commitments to resolve the anomaly of the OTRs," he said.
"Mr Baxter's outlandish claim that the NIO was trying to avoid arresting republicans is nonsense and ignores the virtual amnesty provided to the British Army and RUC for killing hundreds of citizens."
Mr Brush, now a DUP councillor, said he was not surprised by Mr Baxter's claims.
"From the revelations of the get-out-of-jail-free letters, I expected there would be more to come and I still think there will be more revelations to come yet because I think the government has behaved very badly towards the victims of terrorism in this country," he said. "The victims of terrorism seem to be expendable, but the terrorists had to be preserved."
Justice Minister David Ford (left) yesterday briefed members of Stormont's justice committee on the scheme.
He told MLAs Secretary of State Theresa Villiers had apologised to him following the revelations.
"And, for the record, I did ask her if there were any other issues like this 'lurking in the woodwork' as Mr (Patsy) McGlone (SDLP MLA) put it last Tuesday," he added. "She gave me an assurance that there were not."
Mr Ford added: "As I have repeatedly said, my department has had no involvement with the scheme and so does not have information on the requests made nor the content of and names of those to whom letters issued. That information is held by the NIO and the Secretary of State made a statement to the House of Commons last week on the number of cases considered by the NIO."