The Police Ombudsman, Ms Nuala O'Loan, has been called in by the Policing Board to investigate claims by the former head of the Special Branch, Mr Bill Lowry, that he was forced from his job by MI5 to appease Sinn Féin.
A "difficult" meeting of the board yesterday decided that Ms O'Loan, rather than an outside investigator, should examine Mr Lowry's claims.
Chief Supt Lowry led the operation that resulted in the uncovering of the alleged IRA spy ring at Stormont.
He claimed the fallout from the Stormont investigation resulted in his being forced to retire from the PSNI, and that MI5 was directly implicated. Mr Lowry said official anger at his arrest of senior republicans lay behind him leaving the police.
The PSNI chief constable, Mr Hugh Orde, has insisted there was no political interference in the Lowry case.
Meanwhile, the PSNI is today launching a drive to recruit 1,500 part-time officers over the next three years. They will be recruited on a 50:50 Catholic/Protestant basis.
Initially, 100 part-time officers will be recruited in a pilot scheme in Newtownabbey, Lisburn, Banbridge and Coleraine. When the recruitment is completed in 2006 the part-time element of the force will number 2,500.