The Smithwick Tribunal has adjourned with no date for set for its resumption.
Judge Peter Smithwick said that he was "totally dependent" on information which the Tribunal was still waiting to receive.
If and when that material is received will dictate when the Tribunal sits again.
Last week, the Judge stated that he was still trying to obtain information from British security agencies, which he described as "highly relevant" to the Tribunal but which had not been obtained.
Today is the 23rd anniversary of the deaths of RUC Chief Supt Harry Breen and Supt Bob Buchanan.
They attended a meeting in Dundalk Garda Station on the afternoon of 20 March 1989, but died in an IRA ambush just minutes after they left.
The Tribunal was set up to examine claims that a garda passed information to the IRA allowing them time to set up the ambush.
Judge Smithwick said his thoughts were with the families of the two officers as anniversaries bring back the horrors of that day to them.
Much revealed about killings
A representative of the family of Chief Supt Breen said the work of the Tribunal had revealed much about "what was known and seemingly ignored or withheld" relating to the deaths.
John McBurney said the emerging particulars "are quite alarming and at times almost impossible to comprehend" for the family.
The Tribunal earlier heard from a retired British Army major who said he thought the idea that the IRA had members on several roads prepared to ambush two senior RUC officers "lacked credibility."
The Major who served three tours in Northern Ireland was commander of Y Company based in Forkhill at the time of the ambush in which Chief Supt Breen and Supt Buchanan were killed.
The witness, who gave his evidence from behind a screen to protect his identity, also said the watch towers in the South Armagh area were an effective deterrent.
Local people believed they could see a lot more than they actually could.
Asked who was responsible for the listening equipment on the towers the Major, who was in command of the area, said he did not know.
One of the theories put forward in relation to the ambush was that a large number of IRA members were positioned on the different roads from Dundalk to Newry.
However, this witness said that "lacked credibility" given the number of people involved and the frequency of army/RUC patrols.
In the wake of the murders he said there was speculation among those in Forkhill about whether there was a mole who passed information to the IRA but this was not based on any hard information, the witness said.
