THE family of Robert McCartney have vowed that they will not give up their campaign to bring his killers to justice despite three men being acquitted of his murder last Friday.Father-of-two McCartney was stabbed to death after a row outside a Belfast bar in January 2005. Within days Republicans were blamed for the murder.While the IRA denied involvement, it announced that it had expelled three members alleged to be involved in the murder. Sinn Fein suspended seven of its members who had been in the bar at the time of the altercation.Over the last three years McCartney's sisters and partner Bridgeen Hagans took their campaign around the world, including meeting President George Bush and Senators Hillary Clinton and Edward Kennedy.However, the McCartneys' efforts to bring their brother's killers to justice was dealt a crushing blow last Friday when the three men charged in connection with the murder were all acquitted due to a lack of evidence.Trial judge Justice Gillen said that he understood that the McCartney family would be "frustrated and disappointed that whoever it was who cut this young man down in the prime of his life has not been brought to justice.""However, the memory of Mr. McCartney and the rule of law itself would be ill-served by this court failing to observe the high standards of criminal justice and the burden of proof which prevail in courts in Northern Ireland," he said.But the judge warned the three acquitted men that they could face new charges if new evidence emerged."I have no doubt that the investigation into this crime will continue and if new evidence emerges in connection with this murder no-one, including for that matter even the accused in this trial, will be beyond the reach of potential prosecution," he added.Despite the setback McCartney's family insisted that the campaign to bring his killers to justice would not end."It's not over," said Catherine McCartney. "We are very disappointed but not surprised by the verdicts. "We didn't have very high expectations."Given the evidence, I believe that the judge's verdict was correct."The dead man's family accused Sinn Fein and the IRA of obstructing efforts to bring the killers to justice."The police have a wealth of information, a wealth of intelligence but can turn none of it into evidence because people refuse to come forward and stand in a court," she said.Sinn Fein rejected claims that it had obstructed the case."We have urged people with any information to bring it forward to the Police Service of Northern Ireland and will continue to do so," said a spokesperson.Speaking after the court case, McCartney's partner Bridgeen Hagans said, "Our world has been ripped apart and we will never get over this. I can't believe the people who took away my Robert are still out there."People should remember that they could do the same thing again to another innocent family."Pointing to the fact that her sons would never again see their father, she said, "No child at their age should have to be told that their daddy won't be coming home."When they get older they are going to want to know what happened to their father and no mother should have to do this."They have been put through a terrible time and they should not have had to receive counseling at such a young age."It was hard enough watching them grow up without Robert, but after last Friday's verdict it's just even harder."