A former chief investigator of unsolved murders in Northern Ireland has been arrested by officers in connection with the theft of police documents.
Steve Hobbs, 62, was detained and papers seized after a rented house in Hillsborough, Co Down, was raided. Another search was carried out in southern England.
Mr Hobbs is a former officer with the Metropolitan Police and was until recently a senior member of the Historical Enquiries Team (HET) of detectives established to probe more than 3,000 deaths caused by the IRA, loyalist paramilitaries or state security forces.
Earlier this year, a report by Her Majesty's Inspectorate of Constabulary (HMIC) watchdog said the HET treated killings carried out by the army differently to other cases.
It found the HET was illegally investigating deaths involving soldiers with less rigour than cases with no alleged state involvement.
Following the publication of the report work by the HET was suspended. An announcement on the way forward is expected next week about the future of the body.
A police spokesman said a number of items were removed for examination.
It is understood the police do not believe anyone's security has been been compromised.