A well-known republican has been arrested by detectives investigating the murder of Belfast mother-of-10 Jean McConville.
Bobby Storey, 58, was detained in the west of the city.
Officers stressed he was detained as part of the "overall investigation" into the crime.
As well as the murder of the widow in 1972, police are also investigating linked alleged terror offences that happened in the decades since, including IRA pronouncements made about the killing.
It is understood Mr Storey has been detained under the provisions of the Terrorism Act.
The abduction, killing and secret burial of Mrs McConville is one of the most notorious crimes of the Northern Ireland Troubles.
The police case lay effectively dormant for decades until a flurry of activity this year, with a series of arrests made, the most high-profile being the four-day detention of Sinn Fein president Gerry Adams.
Mr Adams, who vehemently denies involvement, was released pending a report being sent to prosecutors for assessment.
Mrs McConville was dragged, screaming, away from her children in the Divis flats in west Belfast by a gang of up to 12 men and women after being wrongly accused of informing to the security forces.
She was interrogated, shot in the back of the head and then secretly buried - becoming one of the "Disappeared" victims of the Troubles.
Her body was not found until 2003 on a beach in Co Louth, 50 miles from her home.
Mr Storey has been taken to the Police Service of Northern Ireland's serious crime suite in Antrim town for questioning.