Judgement has been reserved in the case of Donegal man John Downey who is wanted in Northern Ireland on suspicion of involvement in the murder of two soldiers.
The Creeslough man is appealing against an order by the High Court in the Republic of Ireland to extradite him to Belfast.
Police in Northern Ireland sought his extradition over the murder of two UDR soldiers in 1972.
Alfred Johnston and James Eames died in a bomb in Enniskillen, County Fermanagh.
Mr Downey was previously accused of the murders of four soldiers in the 1982 IRA Hyde Park bombing.
He had been due to stand trial for those murders in 2014, but the trial collapsed when it emerged that he received a so-called on-the-runs letter – a clear written assurance from the government that he would not be tried unless new evidence came to light.
At the appeal hearing in Dublin yesterday, his lawyer argued that the proposed trial in Belfast was “doomed to failure”.
However, counsel for the Minister for Justice and Equality Charlie Flanagan said that there was a degree of “unreality” to the idea that such “on-the-run” letters could be relied upon.