Police believe UDA members were involved in the murder of Catholic community worker Kevin McDaid, the High Court has heard.
Prosecutors also disclosed that 10 people are now under threat as part of an alleged campaign to intimidate witnesses to the attack in Coleraine.
Details emerged as one of the men accused in connection with events surrounding the killing of Mr McDaid was refused bail.
Self-employed joiner David James John Cochrane, 48, of Windyhall Park, Coleraine, faces a charge of affray. He denies the offence.
Crown counsel Peter Coll said it was alleged that Cochrane was part of a group shouting sectarian abuse last month when the father-of-four was beaten to death near his home.
Another local Catholic man, Damien Fleming, was also attacked and serious injured as violence flared after Rangers won the Scottish Premier League football title.
'Fear'
Opposing Cochrane's application to be released, Mr Coll claimed there was a risk of possible interference with witnesses.
"It is the police view that UDA members were involved in the murder of Mr McDaid, the attempted murder of Mr Fleming and the wider incident," he said.
"This has caused widespread fear in the local area. One of the direct effects is that potential witnesses are reluctant to give evidence and fearful for their lives and the lives of family members."
Francis Rafferty, defending, said his client strongly denied being involved in any of the events alleged.
The barrister also highlighted the conflicting accounts given by two witnesses.
After hearing both sides Mr Justice Hart said there were "sectarian overtones" to the attack.
Refusing bail, he said: "It is believed that a terrorist organisation was involved or members of such an organisation were involved in the events of that day."
© UTV News