Two former detectives were arrested today by Police Ombudsman investigators probing the RUC's handling of an inquiry into the murder of a man beaten to death by loyalist paramilitaries near Belfast.
They were detained for questioning about an alleged attempt to pervert the course of justice and misconduct in public office.
Both officers were involved in the investigation into the murder of Raymond McCord Jnr, who was beaten to death near Belfast in 1997 by members of the Ulster Volunteer Force (UVF).
It has been claimed that at least one of those responsible for the brutal killing was working for police Special Branch at the time.
Police Ombudsman Nuala O'Loan is carrying out a major investigation into the scandal. A file has been submitted to the Public Prosecution Service and a report is expected to be published next month.
Two premises were also searched as part of today's arrest operation.
Mrs O'Loan's report of her inquiry into the police investigation is expected to be one of the most damning published, with devastating claims that loyalist paramilitaries working as informers for police in Northern Ireland at that time were involved in a series of killings, but were never charged.
Raymond McCord Jnr, 22, was beaten to death by the UVF in Newtownabbey in November 1997 after falling out with former associates.
The two former detectives arrested today were detained for questioning at separate police stations, the Ombudsman Office said.
Mrs O'Loan's officers carried out the arrest operation and were supported by members of the Police Service of Northern Ireland.
One of the ex-policemen detained was Trevor McIlrath, according to a former colleague whose home in Ballymena, Co Antrim was also searched.
Johnston "Jonty" Brown was overseas on holiday when computer equipment and other items were taken away for examination.
Brown told friends today that McIlrath's home was searched as well. Both officers worked on the McCord inquiry when members of the RUC.
The second former officer held for questioning has not been named.
Brown was interviewed voluntarily by the Ombudsman's team several years ago after leaving the RUC and revealing highly embarrassing and damaging details of Special Branch work with loyalist informers.
He was heavily involved in the police undercover operation which led to the arrest in 1994 and conviction the following year of feared west Belfast UDA boss Johnny "Mad Dog" Adair who was found guilty of directing terrorism.
From his holiday hotel Brown told the Press Association today he expected to be arrested on his return to Northern Ireland.
He said: "This hasn't come as any real surprise, but I've nothing to fear and nothing to hide.
"This is about shutting you up as much as trying to make you amenable for minor breaches of confidence in public office."Reuse content