The 57-year-old woman arrested on Thursday by detectives investigating the IRA murder of Belfast mother-of-10 Jean McConville has been released from custody.
The suspect, who would only have been in her mid-teens at the time Jean McConville was abducted, was detained in west Belfast and taken to Antrim police station for questioning.
She has been released pending a report to the Public Prosecution Service.
The murder and secret burial of Mrs McConville in 1972 is one of the most notorious incidents of the Northern Ireland Troubles.
The arrest came after a veteran republican - 77-year-old Ivor Bell - was charged last month in connection with the killing.
Bell, from Ramoan Gardens in west Belfast, faces counts of aiding and abetting the murder and of IRA membership.
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 50 miles from her home. The IRA did not admit her murder until 1999 when information was passed to police in the Irish Republic.
She became one of the so-called Disappeared, and it was not until August 2003 that her remains were found on Shelling Hill beach, Co Louth.
Nobody has been charged with her murder.