Gerry Hutch will find out today if a secretly recorded conversation can be allowed into evidence.
The court has not sat since Tuesday because judges in the trial are considering the legal arguments on the admissibility of the contentious piece of evidence.
Mr Hutch is accused of the murder of David Byrne, who was shot dead at the Regency Hotel in Dublin in 2016; Mr Hutch denies killing him.
After listening to ten hours of a recorded conversation between Mr Hutch and Mr Dowdall, as they drove to Northern Ireland to allegedly meet with Republican contacts of Mr Dowdall’s one month after the shooting, the judges heard from both sides on whether the evidence should be allowed into the case.
The defence claims it is inadmissible; they say it was obtained unlawfully and argue most of it was recorded outside the jurisdiction.
The prosecution contends there is no issue because the bug was deployed, removed and later downloaded on this side of the border.
The judges will make their ruling later this morning.
Main image: The Special Criminal Court. Picture by: Leah Farrell / RollingNews.ie