Two women who were arrested yesterday by PSNI detectives investigating the murder of Jean McConville over 40 years ago have been released.
The women, aged 57 and 60, were freed pending a report to Northern Ireland's Public Prosecution Service.
The abduction, murder and secret burial of Mrs McConville in 1972 is one of the most notorious incidents of the Northern Ireland Troubles.
Nobody has ever been charged with her murder.
After decades without significant developments in the criminal investigation, there have now been six arrests within a month.
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.
Mrs McConville 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 gardaí.
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.