A file is being prepared for the Director of Public Prosecutions
A man arrested last week in connection with the murder Garda Adrian Donohoe was released by gardaí last night.
A file is being prepared for the DPP.
The man, aged in his 60s was arrested in Dundalk on Monday night.
Gardaí are continuing to question another man, aged in his 20s, who was arrested last Sunday.
Detective Garda Donohoe was shot dead on the 25th January 2013.
The father of two died during an armed robbery at the Lordship Credit Union in Belurgan.
Gardaí have been working with several international police organisations, including the FBI and PSNI, as part of the investigation into Detective Donohoe's death.
This morning, they said their investigations are ongoing.