Speaking at a republican commemoration in Derry, Adams also said he will not let the issue drop until the killers were held to account and that he was angered they had not complied with repeated requests to give full statements on their role in the murder.
Adams told those gathered at the event that many republicans felt McCartney’s murder had been exploited.
“What annoys me the most is not the criticism from the two governments,” he said. “If those who fear the growth of Irish republicanism are given an opportunity to undermine it, they will take that chance.
“A small group of individuals are not prepared to face up to their responsibilities. Instead these cowardly individuals will allow an avalanche of propaganda aimed at criminalizing republicanism.
“So let me be clear — I am not letting this issue go. Whatever way people feel about how the McCartneys are running their campaign, this family have the right to truth and justice.”
The McCartney family themselves say they may consider taking a civil action against those responsible for the murder, whose names are being openly spoken in Belfast, but that they would prefer criminal charges in court.
Meanwhile, in its Easter statement, the IRA said it moved “quickly to deal with those involved. We have tried to assist in whatever way we can,” it said. “Unfortunately, it would appear that no matter what we do it will never be enough for some.
Meanwhile, Sinn Fein’s chief negotiator, Martin McGuinness, said the IRA statement confirming it had offered to shoot the killers had been a huge mistake. He said the offer had detracted from its attempt to dispel claims it was covering up the murder.
“What we have to acknowledge first and foremost is that the IRA statement, that it was prepared to shoot the people responsible was, in my opinion, a huge mistake,” he said.
But, he added, the same statement had “dispelled any notion that they were prepared to cover up for the people who murdered Robert McCartney.” Shooting those responsible, however, he said, “would have been terribly wrong, it would have been deplorable.”
McGuinness said he remained hopeful all sides in Northern Ireland’s peace process were ready to make progress on achieving a deal to restore power sharing after the British general election in May.
“What we have to do is bring about a very clear situation where the issue of the IRA is dealt with,” he said. “We tried to do that last December; it didn’t work because Ian Paisley fluffed it at the last.
“My sense of it is, listening to the comments of Ian Paisley, the comments of Tony Blair, the comments of others within the process, that people recognize that immediately in the aftermath of that election we are going to have to crack out a deal.” This was also a recurrent theme in other republican speeches at commemorations. Adams signaled republicans would face hard choices as they pursued peace and a united Ireland. Those who wanted most change had to risk most, he said.
The DUP leader, the Rev. Ian Paisley, however, has said substantial time will have to pass after IRA disbandment for people to be convinced its activity had ended. He repeated his demand for complete decommissioning with witnesses and photographic evidence and said the last talks process could not be renewed as the process was now in a completely different situation.
The British Northern Ireland secretary, Paul Murphy, also said there was no hope of political progress until the issue of IRA was resolved.
In his Easter speech, Adams was highly critical of the Irish government’s record.
“The process is in serious difficulty”, he said. “Much of this is being driven by an Irish government fearful of the growth of Sinn Fein and our determination to challenge the mess the establishment parties are making.”