One of the six is prominent republican Colin Duffy
Six people being held in connection with the murders of two soldiers and a police officer in NI have launched a High Court challenge to the extension of their detention period.
Four are being questioned about the Real IRA shootings of Sappers Mark Quinsey, 23, and Patrick Azminkar, 21.
They were shot outside Massereene Army barracks on March 7.
The other two were arrested in connection with the murder of Constable Stephen Carroll.
Constable Carroll was shot by the Continuity IRA in Craigavon, County Armagh, two days later.
Only one of the six, prominent republican Colin Duffy, who is being questioned about the soldiers' murders in Antrim, was present as his lawyers attempted to overturn a decision which allows police to keep them in custody for an extra seven days.
Judges granted anonymity to the other five, who are all seeking an urgent judicial review on the same basis that the move was unlawful and breached their right to liberty under the European Convention on Human Rights.
None have been charged, but at the weekend a County Court Judge granted the extension request brought under the Terrorism Act 2006.
Handcuffed and flanked by police, Duffy, 41, smiled up at family and friends in the public gallery after being allowed into the courtroom by the three judges hearing the application.
Some of his supporters later confronted officers and shouted abuse as he was led away when the case was adjourned to allow the judge to give reasons for her decision.
Earlier, Barry Macdonald QC, for the six applicants, said the reason they were still in custody was because police were waiting the outcome of forensic tests.
The barrister claimed this did not warrant a decision that their continued detention was necessary.
He also argued that the judge failed to consider whether there was a persisting reasonable suspicion over any of the applicants, and that she failed to give reasons for her decision.
He told the court that the final police interview with Duffy was carried out on March 20, with no evidence put to him during questioning.
"It appears in the present cases that in broad terms the police have effectively completed their interviews with the applicants," he said.
"The applicants are being detained in cells without requirement for interview. They are being detained there while the police await the outcome of forensic examinations."
Under amendments to the Terrorism Act suspects can be held for a maximum of 28 days before they must be charged or released
According to Mr Macdonald it is not necessarily expected that any of his six clients will be formally accused before that period expires.
"Because there has been no charge the applicants are not entitled to apply for bail," he added.
"So, although the applicants can be detained under these provisions for up to 28 days, they have fewer rights - and indeed no right to bail - than a person for whom there is sufficient evidence to bring a criminal charge."
But Paul Maguire QC, for the Crown, countered by stressing the test for continued detention was on the balance of probabilities.
"We say in the course of a lengthy hearing the judge was entitled to make a conclusion about that and has done so," he said.
Mr Maguire also rejected claims that the move was incompatible with the Human Rights legislation.
"It has been held by the Strasbourg Court that arrest under anti-terrorism legislation in Northern Ireland is an arrest that falls within Article 5.1 (C) of the Convention," he added.
After hearing both sides Lord Chief Justice Sir Brian Kerr said a decision would be made on the application after reasons for the extension are given on Tuesday.