The body set up to monitor the IRA ceasefire could not make an assessment on who murdered former Sinn Fein official-turned-British spy Denis Donaldson.
Even though the Independent Monitoring Commission's latest report stated that the Provisionals had made substantial progress in winding down terrorist activities, the four-member panel failed to reach any judgment on whether members of the organisation were behind the murder.
In April, Mr Donaldson was blasted with a shotgun in a remote cottage in Glenties, Co Donegal, in the Irish Republic, where he had gone into hiding after admitting publicly that he had spied on Sinn Fein colleagues for more than two decades.
At the time security sources believed disaffected former IRA comrades were behind the attack.
Mr Donaldson, a friend of IRA hunger striker Bobby Sands, was a trusted member of Sinn Fein when he was one of three men arrested in October 2002 for allegedly operating a republican spy ring at Stormont.
The allegations led to the collapse in 2002 of power-sharing between unionists and nationalists at Stormont.
Northern Ireland's politicians have not been able to revive devolved government since.
Within weeks of the case against Mr Donaldson and his co-accused collapsing last December, he was unmasked by Sinn Fein leader Gerry Adams as a spy and admitted in an Irish television interview to having been in the pay of British intelligence.
With Wednesday's report seen as being critical to next week's talks to revive devolution in Northern Ireland, the IMC's reluctance to make an assessment of who carried out the murder will fuel unionist scepticism about those negotiations.
The Commission devoted just one paragraph in its report to the killing, stating: "In our previous report we mentioned the murder of Denis Donaldson in Co Donegal on April 4, 2006. We said we were not able to attribute responsibility for the murder and would continue to monitor the situation. There has been no change in this situation to date."
