A man in his 40s is due to appear in the High Court this morning as part of an investigation into the murder of prison officer David Black.
The 52 year old was shot dead as he drove along the M1 motorway in County Armagh on his way to work at Maghaberry Prison in November 2012.
As part of a joint operation by the Gardaí and PSNI – a man in his 40s and a man in his late 50s were arrested yesterday afternoon in County Donegal.
The man in his 40s is due to appear before the High Court this morning on foot of a European Arrest warrant.
The second man is being held at Letterkenny Garda Station.
As part of the operation a 47 year old woman was also arrested in Belfast and is being questioned at Musgrave Serious Crime Suite.