John Carthy's sister, Marie, is questioning why the Garda Emergency Response Unit didn't use non-lethal equipment in their possession to resolve the armed siege, which ended in the shooting dead of her brother in April 2000.
The Abbeylara tribunal heard today that the ERU had pyrotechnic equipment including flares, two bang distraction devices and smoke canisters.
Marie Carthy told reporters she was surprised at today's revelation, and cannot understand why the equipment was not used.
She said: "We are very happy that it has finally begun, but the one thing we are very surprised about is that we have heard that the ERU had with them two canisters, I think it was for smoke or tear gas or something, and I don't know why they didn't use them at the time because they cut off the TV cable, the aerial for the house, and they could have used it then.
"They were looking in in the morning when John was resting and asleep on the couch and they never used it then."