A man has been arrested tonight in connection to the Belfast murder, two week’s ago, of Robert McCartney.
Meanwhile, the Provisional IRA has distanced itself from the murder of the Belfast man.
In a statement, the organisation said denied any involvment in the killing and said no one should hinder or impede the dead man's family in their search for truth and justice.
It also said those who were responsible for the brutal killing must take responsibility for their own actions which run contrary to republican ideals.
Robert McCartney's family met with the US Consul General for Northern Ireland, Dean Pittman earlier today.
After meeting with Mr Pittman, the relatives said they had received assurances that the case would be raised with officials in Washington.
Paula McCartney, sister of the murdered man, insisted the tireless campaign to flush out those responsible would not be denied.
The McCartney family claim that witnesses have been ordered to keep silent as part of an intimidation campaign.
They want the US government to intervene as they seek to have the killers brought to justice.
They claim that individual IRA members were involved but believe the paramilitary group did not sanction the killing.
SDLP leader Mark Durkan is due to raise the case with US President George W Bush's Special Envoy for Northern Ireland, Mitchell Reiss, during a visit to Washington this week.
Senior Sinn Féin figures have come out against those responsible for the attack, claiming they would have no part in hiding the killers and that the family deserved to see them captured.
Sinn Féin MLA Gerry Kelly, who has visited members of the McCartney family, said: 'I don't care who was involved in this horrible killing. Had I been anywhere near where this terrible killing took place, I would immediately have gone to the family and made a statement of what happened there.'
'Let me be clear, there will be no cover up. Sinn Féin people will not be involved in covering up this action,' he added.
