The bomb was placed in a taxi which was hijacked in north Belfast
A man arrested by police investigating the Real IRA bomb attack on Palace Barracks in Holywood last month has been released without charge.
The bomb exploded outside the Army base which houses MI5's Northern Ireland headquarters on Monday 12 April.
The man was arrested in the Dunmurry area on Saturday morning.
The car bomb went off minutes after policing and justice powers were devolved back to Northern Ireland from Westminster.
An elderly man who was walking near the barracks at the time of the bomb was treated for minor injuries.
The bomb was placed in a taxi, which had been hijacked in the Ligoniel area of north Belfast, about seven miles from Holywood, at about 2150 BST.
The driver was held hostage by three men for about two hours before being told to drive his taxi to the barracks.