The senior Garda officer responsible for calling in the Emergency Response Unit in the Abbeylara incident said he had thought of the Brendan O'Donnell and John Gallagher cases when he heard about the siege.
Brendan O'Donnell killed Imelda Riney, her son Liam and Father Joe Walsh at Whitegate in Clare in 1994. John Gallagher shot and killed his former girlfriend Ms Anne Gillespie and her mother, Annie, in the grounds of Sligo General Hospital in 1988.
Assistant Commissioner Tony Hickey learnt of the Abbeylara siege from Chief Supt Padraig Tansey about an hour after it began. He was told, by telephone, that Mr Carthy was a manic depressive, had a shotgun and had fired shots.
"And I don't want to cast any aspersions on John Carthy but I must say that at the back of my mind, considering what has happened in rural Ireland in recent years, I thought of Brendan O'Donnell and John Gallagher and what they did," Mr Hickey told the sub-committee.
"It wasn't focused entirely on this. I was also conscious, for instance, that in my region in November 1997 a local man had a bit of aggravation with neighbours. On the surface there didn't seem to be huge provocation and one afternoon he shot a husband and wife."
Mr Hickey referred to other siege situations where local gardai came on the scene and retrieved guns. Having been briefed, and bearing in mind that the situation might have resolved itself before the Emergency Response Unit got to Abbeylara, he decided to call in the unit.
The Garda Commissioner, Mr Pat Byrne, was asked why the FBI was later called in to assess the handling of the incident. He said he wanted to use a police force that was "extremely neutral in so far as police activity in this country is concerned".
"Even though they [FBI] have their problems, as do all police forces, they are looked upon as those that offer best practice and excellence in situations like this and are brought in by other police forces right around America in confrontational situations, especially in hostage rescue," Mr Byrne said.
Asked if gardai were instructed on the degree of force to be used, he said it was not practical to have such regulations. "It becomes judgmental," he said.
"If, at the end of the day, the first shot that was fired by a very well trained officer had done what he wanted to do, shot him in the leg and broken his leg, we wouldn't be here today."
Mr Byrne said he still stood by the regulations in place and stood by how they were interpreted by his officers on that day.
On the ERU weapons, he said there was no such thing as a non-lethal weapon.
"There is a principle that in dealing with a person who is armed with a loaded firearm that one does not use less than lethal weapons - that is a view," he said. Asked if it was his view, he said he did not have a view on it at the moment.
The Garda Siochana was looking at the possibility of using "less than lethal" weapons, he said.
