Irish police have blamed a legal logjam over accessing evidence from another force for the 17th adjournment of an inquest into the death of murdered IRA spy Denis Donaldson.
A coroner in Co Donegal granted the garda request to postpone the case until the spring, but described the number of times the hearing has now been put back as "unprecedented".
Gardai believe Mr Donaldson's killers can still be caught and do not want an inquest to proceed while their criminal investigation remains live.
Mr Donaldson, 55, a senior Sinn Fein official and close colleague of party president Gerry Adams, was shot dead at an isolated cottage near Glenties in Co Donegal in April 2006.
He had been living there since his exposure as an MI5 agent the previous year.
Dissident republican group the Real IRA claimed responsibility for the murder three years later but the circumstances surrounding Mr Donaldson's outing and subsequent assassination have been shrouded in mystery.
On Wednesday, Garda Superintendent Michael Finan told coroner Denis McCauley the murder investigation continued to make progress and detectives were following "significant and definite leads".
Last year, gardai made a mutual assistance request to a police force outside the Irish Republic in a bid to gain potentially "significant" material.
Mr Finan said that had still not been obtained.
"This adjournment is necessary to ensure that all available evidence is gathered and presented to the DPP (director of public prosecutions)," he said.
The officer added: "There are genuine legal reasons for the delay providing the material we are seeking."
Mr McCauley, sitting in Letterkenny, said he would agree to the latest adjournment because he felt there was still investigative "activity" .
"There's a criminal investigation taking place and there's the possibility of consideration of an actual criminal prosecution," he said.
The family of Mr Donaldson have been highly critical of the Irish police's handling of the investigation.
Relatives have stayed away from a number of recent inquest hearings in protest at the repeated requests for adjournment.
Neither relatives or their legal representatives attended the latest hearing at the Mount Errigal Hotel.
A letter from their solicitor, read out by the coroner, stated that the family considered attendance to be a "pointless exercise".
Referring to the remarks, Mr McCauley added: "I can understand their frustration at this process but I must admit from what Superintendent Finan told me today I'm happy to grant an adjournment for a further three months, at which point hopefully we'll have further information and maybe even a decision."
The next hearing has been scheduled for April 13 next year.
Over the last two years, lawyers acting for the family of Mr Donaldson have threatened legal action against the gardai on a number of occasions.
Relatives allege the force is in contravention of the Irish state's obligation to conduct a proper and timely investigation under the European Convention on Human Rights (ECHR).
In the wake of the 17th adjournment of the inquest, a family statement reiterated their intent to seek "appropriate remedies" in the courts.
"A decade on, the Donaldson family's patience is now exhausted," said the statement issued on behalf of the family by Belfast-based solicitors Madden and Finucane.
"The Irish state must be held to account for its violation of our right to an Article 2 ECHR-compliant investigation, just as much as those responsible for causing Denis's murder and the family's ordeal.
"We will therefore be shortly consulting with our legal advisers with a view to securing appropriate remedies at both domestic and European level."
The statement said the family would also be submitting a new complaint to the Garda Siochana Ombudsman Commission.