Two men who were being questioned over the 2011 murder of a police officer have been released unconditionally.
Constable Ronan Kerr, 25, was killed by a booby-trap car bomb in Omagh in County Tyrone on 2 April six years ago.
The attack was carried out by dissident republicans.
A 27-year-old man was arrested in Omagh and a 40-year-old man was brought into police custody from prison.
They were questioned under the Terrorism Act in connection with the murder but were released on Wednesday evening.