A lawyer representing the Carthy family said he intended to cross-examine every member of the Garda who had an input into the preparation of the Garda report on the shooting at Abbeylara.
Mr Michael O'Higgins SC told the Oireachtas sub-committee the Garda report presented a picture of Mr Carthy which was "absolutely unrecognisable" to his family and those who knew him.
He said he would further seek to impugn those who had any involvement with Mr Carthy in the 24 hours up to his death.
Mr O'Higgins said his clients welcomed the opportunity which the sub-committee inquiry provided to ask questions about what happened in Abbeylara on April 20th last year. He complimented the subcommittee on drawing up a wide schedule of issues to be examined.
Notwithstanding this, Mr O'Higgins said he supported the contention of Mr John Rogers SC, for 25 named gardai, that it would be preferable if the investigation was carried out in a judicial forum in the form of "a tribunal of some sort".
However, if the sub-committee did not endorse this view, his clients were happy to participate in the Oireachtas inquiry. "It would be our intention then to roll up our sleeves and get involved in the very important issues that have to be raised," he said.
Mr O'Higgins expressed alarm at a reference made by the sub-committee's chairman, Mr Sean Ardagh TD, in his opening statement, to the fact that the direct part played by lawyers during hearings would "be resorted to only where absolutely necessary".
Mr O'Higgins said he could not understand how a person would have to be represented in a "strictured" fashion.
"If it becomes clear we are in some way tramelled or hampered, or an inability arises to discharge our professional duty to our clients, well, in those circumstances, we will be left in the unhappy position of putting that on the record and withdrawing from the proceedings," he said.
He added that his clients had made a formal submission to the sub-committee setting out a number of issues which concerned them, including the exclusion of State Pathologist Dr John Harbison's report from the Garda report, and the failure to give Mr Carthy access to a solicitor.
Outlining some of the background to the shooting, he said Mr Carthy emerged from his house and took one cartridge from a double-barrel shotgun and threw it away. He suggested this was not an act of aggression on the part of a man who was psychiatrically ill and who had been surrounded for 24 hours by an anti-terrorist unit.
Having considered the point raised by Mr O'Higgins on legal representation, the sub-committee said each person before it would "be afforded all necessary facilities consistent with constitutional and legal rights".