A man arrested in connection with an IRA bomb attack that killed a Catholic nun and three police officers in the North has been released pending a report to prosecutors.
The 54-year-old suspect was detained at Belfast International Airport on Monday morning.
He was the second man questioned in relation to the 1990 attack in Co Armagh in less than a week.
A 55-year-old man arrested last Thursday was also released pending a police file being submitted to Northern Ireland's Public Prosecution Service.
Sister Catherine Dunne, Constable William Hanson, Reserve Constable Joshua Willis and Reserve Constable David Sterritt were killed when a landmine exploded on the Killylea Road, Armagh, on July 24, 1990.
Another woman was seriously injured in the blast.
The arrests have been carried out by the PSNI's legacy investigation branch.