The Garda ballistics expert who investigated the scene at Abbeylara said he did not examine the guns of the local gardaí who were at the siege, because he believed they would have handed in their weapons if they had discharged them.
Mr Seamus Quinn, a retired detective sergeant with the ballistics section of the Garda Technical Bureau, told the tribunal he would have expected any garda who fired a shot to surrender his weapon for examination because it was against regulations not to do so.
Mr Quinn appeared before the tribunal last December but was recalled by Mr Justice Barr to explain why he did not examine the guns of local officers.
Mr Quinn arrived at the scene at around 9 p.m. on April 20th, 2000, some three hours after John Carthy had been shot dead by gardaí.
He said he asked Sgt Sean Leydon, the crime scene examiner, to gather "all the Garda fire arms at the scene since the incident commenced".
However, three days later he narrowed this instruction to include only those guns held by members of the Emergency Response Unit at the scene.
He made this decision following the the post-mortem examination, the search of the scene and information received in the intervening days.
The post-mortem showed that Mr Carthy had been shot four times and these four bullets had been accounted for by two ERU members.
No other spent cartridges were found at the scene and no local gardaí had said they had fired a shot.
"I do believe that if any other weapon had been discharged it would have been handed in," Mr Quinn said.
