Leading republican Marian Price has been released by detectives investigating the murders of two soldiers outside Massereene barracks in Antrim.
Police said a report will now be prepared for the Public Prosecution Service.
Heavily armed police raided Price's home in the Andersonstown area of west Belfast on Tuesday and she was taken away for questioning about the Real IRA killings last March.
The 55-year-old was arrested along with a 39-year-old man, who was detained 40 miles away in Coalisland, Co Tyrone.
The man has been released unconditionally.
Only two men have been charged so far with the murders of Sappers Patrick Azimkar, 21, from London, and Mark Quinsey, 23, from Birmingham at the military base - prominent Co Armagh republican Colin Duffy, 41, and Brian Shivers, 44, from Magherafelt, Co Londonderry.
Price and her sister Dolores were among those convicted over the 1973 IRA bombing outside the Old Bailey in which one person was killed and around 200 others injured.
She is a leading member of the 32 County Sovereignty Movement, considered to be the Real IRA's political wing.
© UTV News