Six people arrested over the dissident republican murders of two soldiers and a policeman yesterday launched a new High Court challenge to anti-terror laws.
The suspects, who include high-profile republican Colin Duffy, have already won a legal case against a decision to extend their period in custody.
But their lawyers are now seeking a declaration that the relevant terrorism legislation was incompatible with their right to liberty under the European Convention on Human Rights.
Duffy (41) was the only one of the six to have been charged following questioning by police.
The Lurgan man is accused of the murders of Sappers Mark Quinsey and Patrick Azimkar outside Massereene Army barracks in Antrim in March.
Another three taking the judicial review were also detained over those shootings, while two more were held in connection with the murder of Constable Stephen Carroll in Craigavon, Co Armagh, two days later.
None of these five can be identified after they were granted anonymity by judges hearing the case.
Proceedings began earlier this year when a County Court judge granted police more time to question all six under the amended Terrorism Act which allows for suspects to be held for up to 28 days before they must be charged or released. Although this extension was quashed, a further claim that it breached their Convention rights was set aside at the time due to the urgency of the case.
Lawyers for Duffy and the others returned to the High Court to request a declaration.
Legal sources predicted that if the application is successful it would have impact not only on those detained for dissident republican activity, but also for any Islamic terror suspects in the UK.
The hearing continues.