The Garda Síochána Ombudsman Commission (Gsoc) must apply to the High Court for transcripts relating to appearances before the Special Criminal Court of the man who killed Garda Anthony Golden.
Adrian Crevan Mackin shot dead Garda Golden on October 11th, 2015, in Omeath, Co Louth before he took his own life.
The Special Criminal Court was told on Monday that a “public interest investigation” has been launched by Gsoc following complaints it received about “the nature of some interactions it is alleged members of An Garda Síochána had with Mackin both prior and subsequent to his arrest in January 2015”.
The court heard the investigation is ongoing.
Counsel for Gsoc, Ronan Kennedy BL, applied on Monday for the court transcripts.
He said Mackin had been charged before the Special Criminal Court in January 2015 with membership of the IRA and his case came before the court on a number of occasions.
Mr Kennedy applied for transcripts of the 12 occasions Mackin's case was mentioned at the court and said Mackin had been granted bail by the court.
He said Jon Leeman, a senior investigations officer with Gsoc, had sworn an affidavit on June 20th seeking the transcripts.
In a ruling from the three-judge court on Wednesday, Ms Justice Isobel Kennedy said the non-jury court did not have jurisdiction, neither inherent nor express jurisdiction, to accede to the application.
She said the High Court had jurisdiction and it was a matter for Gsoc whether it wished to make an application there.
Ms Justice Kennedy, presiding alongside Judge Gerard Griffin and Judge Gerard Haughton, said it would be more appropriate for the application to be made before a different High Court judge, rather than her.