Northern Ireland's policing board was today urged to call a public inquiry into the sudden departure of a senior Special Branch officer in Belfast.
Mr Bill Lowry, who headed the operation against a suspected IRA spy ring at Stormont, quit the force last month.
Chief Constable Mr Hugh Orde today rejected claims there had been any political intervention in Mr Lowry's decision to take early retirement.
During a heated meeting at the board's headquarters, he insisted: "I came under no pressure whatsoever to encourage anyone to leave the Police Service of Northern Ireland."
But Democratic Unionist Party member Mr Ian Paisley Junior later demanded a full investigation to establish the full facts behind the chief superintendent's decision to abruptly end 30 years of service.
He said: "There's prima facie evidence that there's more to this than meets the eye.
"Was there political interference from London?
"Was Bill too successful in the type of people he was arresting?" It is understood the board was today seeking legal advice over a letter it had received from Mr Lowry.
His decision to stand down so soon after playing a key role in the raid on Parliament Buildings and the arrest of four people, including Sinn Féin's administration chief at Stormont, Mr Denis Donaldson, for allegedly gathering intelligence, stunned many friends and colleagues.
Mr Orde told the scrutinising body he was dismayed to lose all experienced officers.
"However, if an officer chooses to retire, it's entirely appropriate for them to do that," he said.
PA