The family of a man murdered in Belfast last month has held a private meeting with Sinn Fein President Gerry Adams.
Robert McCartney, 33, was killed near Belfast city centre
Robert McCartney, 33, was stabbed in the city centre on 30 January.
His family has accused republicans of pressuring witnesses not to talk, although they welcomed an 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.
He added that those responsible for Mr McCartney's death should be brought to justice.
Mr Adams said that he was told up to 70 people, and up to 21 this week, had already come forward with information about his death.
The meeting took place on Thursday.
Mr Adams was speaking in Dublin at the launch of a campaign to urge the Irish government to prepare a discussion document on Irish unity.
Earlier this week, the McCartney family met with Irish Foreign Minister Dermot Ahern and Fine Gael leader Enda Kenny in a bid to win support for their campaign to find those responsible for his murder.
Taoiseach Bertie Ahern has said that a test of Sinn Fein's stated opposition to criminality would be to turn in the killers.
No-one has been charged in connection with the killing, although it is believed there were up to 70 witnesses to the crime.