A man has been released without charge by police investigating the killing of Robert McCartney in Belfast.
Robert McCartney, 33, was killed near Belfast city centre
It is understood he had handed himself in at Musgrave Street PSNI station and was accompanied by his solicitor.
On Friday the IRA said it had expelled three of its members over suspected involvement in the killing, which followed a row in a bar in the city.
The McCartney family have welcomed the expulsions, but have also said the move does not go far enough.
The 33-year-old father of two died in hospital after being stabbed.
Mr McCartney's sister Catherine, said all of those involved in the killing should now come forward.
Mr McCartney's sisters called on all those involved to come forward
"The IRA investigation was carried out behind closed doors therefore we are not accepting or confirming that outline," she said.
"The only way the family will know the truth is if we can hear witnesses' statements in a court.
"We believed that between 12 and 20 people were involved in the events of that night. Not all of them, we understand, were IRA members but we want all people to be encouraged or persuaded or to hand themselves in."
Sinn Fein leader Gerry Adams also said that if he had witnessed the murder he would give evidence in court.
Mr Adams said "any self respecting republican" had a responsibility to come forward if they witnessed the fatal assault.
"Had I found myself in Magennis's Bar and was caught up in these dreadful events, I would now be making myself available to the court as the McCartney family have asked," Mr Adams told the BBC's Today programme on Saturday.
"I say that mindful of all the difficulties that we have had trying to straighten out and get a proper judicial system and so on, but I think that this is such a serious situation."
The IRA said one of those expelled made a statement to a solicitor and called on the others to take responsibility.
Two of the men dismissed were described by the IRA as "high ranking volunteers".
The expulsions came after what the IRA called "an investigation" into last month's killing.
Mr Adams said those involved had a responsibility to come forward
DUP assembly member Ian Paisley Jnr said: "No one should be fooled by this diversionary tactic of a pretend purge of the IRA ranks.
"The statement only highlights the confusion that exists within the IRA who last week told us they were not involved in criminality and tonight pretend they have purged those who are criminals."
SDLP leader Mark Durkan said that, whilst he welcomes the IRA shift in position, he does not believe it will lead to justice being done in court.
"It was only through the challenge of the McCartney family that Sinn Fein has had to take a different track that comes a bit closer to the truth but doesn't come the whole way to justice," he said.
Ulster Unionist Sir Reg Empey said unless the expulsions were accompanied "by the names of the individuals involved in a way that will lead to police prosecution", the statement would be viewed as little other than "a cynical face-saving exercise".
The IRA statement came 24 hours after Mr Adams met the McCartney family.
The family had accused republicans of pressuring witnesses not to talk, although they welcomed an earlier IRA statement urging his killers to come forward.
Mr Adams described the meeting as "constructive".
"There is an onus on us to do everything we can to bring closure to this family," he said.