All four suspects arrested so far in connection with the murder of Bangor man Mark Christie last week have been released without charge.
Three men arrestedon Thursday were freed late on Friday, while the fourth, who was taken in for questioning on Friday, was released without charge on Saturday.
Mr Christie (36) was "hacked to death in the street", according to the PSNI. He was chased from the vicinity of a house in the Owen Roe Drive area of the loyalist Kilcooley estate in the Co Down town by a gang of at least six men with weapons.
He was caught and severely assaulted a short distance away and died at the scene soon afterwards.
The victim had been given a suspended sentence for assault the week before the attack took place.
Widely held beliefs that loyalist paramilitaries were behind the murder has led to renewed pressure on the Ulster Unionists to end their formal link with the UVF-aligned Progressive Unionist leader David Ervine at Stormont.
Mr Ervine was admitted to the UUP group in the Assembly in a tactical move which would boost UUP representation in any future agreed Executive should power sharing be restored.
The decision, which is to be reviewed by the party next month, was strongly opposed by North Down MP Lady Sylvia Hermon, in whose constituency the Christie murder was carried out.