Detectives investigating the IRA murder of Belfast mother-of-10 Jean McConville more than 40 years ago have arrested a 57-year-old woman.
The suspect was detained in west Belfast and has been taken to Antrim police station for questioning, a spokesman from the Police Service of Northern Ireland (PSNI) said.
Mrs McConville was abducted and murdered in 1972.
Nobody has ever been charged with her murder.
After decades without significant developments in the criminal investigation, today’s arrest is the fourth made by detectives within a month.
In March veteran republican Ivor Bell (77) was charged in connection with the killing. Mr Bell, from Ramoan Gardens in west Belfast, faces counts of aiding and abetting the murder and of IRA membership.
Another 57-year-old woman and a 56-year-old man, arrested separately in west Belfast earlier this month, were released from custody after questioning. Police are preparing a report on the woman for assessment by prosecutors.
Mrs McConville, a widow, was dragged away from her children in her home in the Divis flats, west Belfast, by an IRA gang of up to 12 men and women after being accused of passing information to the British army in the city.
An investigation later carried out by the Northern Ireland Police Ombudsman rejected the claims that she was an informer.
She was shot in the back of the head and buried 80kms from her home. The IRA did not admit her murder until 1999 when information was passed to gardaí.
One of the so-called Disappeared, her remains were found on Shelling Hill beach, Co Louth in August 2003.