Irish Prime Minister Brian Cowen and President Mary McAleese at the Easter Rising Celebrations in Dublin on Sunday

Irish police say they still have an open mind on which group murdered Republican double agent Denis Donaldson despite an admission this week by the Real IRA that they did it. It’s the first public claim by anybody of responsibility for the killing three years ago in the hills of Donegal.

Donaldson was shot dead in his hideaway cottage home after admitting spying for the British for 20 years.

At an Easter Monday commemoration ceremony in Derry, just across the border from Donegal, the Real IRA also attacked the peace process and delivered a stinging denunciation of Sinn Fein’s Martin McGuinness for recently describing republican dissidents as “traitors.”

In addition, the dissidents warned civilians who continue to provide services to the police in Northern Ireland that they will be “executed.”

Around 200 people attended the Easter demonstration at the city cemetery in Derry. A color party bearing flags and wearing berets was at the centre of the event. Martin Galvin, a former director of the Irish American group Noraid which helped support the IRA's campaign during the Troubles, was present.

A masked man appeared from the crowd and read a prepared statement. He said, “Denis Donaldson was a traitor and the leadership of the Provisional movement, under guidance from the British government, made provision for Donaldson to escape Republican justice.”

There was confusion when the reader then omitted the next line from the statement, copies of which were circulated to the media before the gathering.

It was, “It fell to the volunteers of Oglaigh na hEireann (IRA) to carry out the sentence and punishment demanded in our army orders and by the wider republican family.”

Leaders of the 32 County Sovereignty Movement, which supports the Real IRA and which organized the commemoration, approached reporters at the ceremony immediately after the statement was read and told them the omission was an error and that the claim the Real IRA killed Donaldson was still valid.

A day beforehand, the Dublin paper the Sunday Tribune carried an interview with a Real IRA Army Council representative who said Donaldson was killed by two people who, armed with a sledgehammer and shotgun, broke down the door of his hideaway cottage in the hills outside Glenties, Co. Donegal, on April 4, 2006.

The representative told the paper that there was a struggle but Donaldson didn’t cry out or plead for mercy and remained silent all the time.

Two months ago an inquest on Donaldson was adjourned for a third time until February 4 next year when Gardai said they were following a new line of inquiry into the murder.

Donaldson, 56, was a senior Sinn Fein figure who headed his party’s support team at Stormont and had been operating as a British spy for 20 years.

The Real IRA representative also told the Tribune that the Real IRA plans to launch attacks in Britain “when it becomes opportune,” although he added that there will not be a return to a sustained campaign of violence. Instead, there will be a “tactical use of armed struggle” against high-profile targets when the opportunity occurs.

The representative added, “Taking military action against Sinn Fein leaders who are British ministers, or who urge Nationalists to inform on us, isn’t high on our agenda at the moment. However, that isn’t to say this position won’t change and, indeed, change quickly under certain circumstances.”

It was the first interview with a Real IRA Army Council representative since it claimed its members carried out the attack on Massereene Army barracks in Antrim last month that claimed the lives of British soldiers Mark Quinsey, 23, from Birmingham and Patrick Azimkar, 21, from London.

Meanwhile, in Dublin, some 2,000 people gathered outside the GPO to mark the Easter Rising on Sunday, including President Mary McAleese and Taoiseach Brian Cowen.