Labour TD Alan Kelly has told the Dáil that gardaí gave guns to Evan Fitzgerald, the 22-year-old who was facing firearms charges but died from a self-inflicted gunshot injury at a shopping centre in Carlow on 1 June.
Addressing the Taoiseach under privilege Deputy Kelly said: "We now know the guns were actually given to him by An Garda Síochána".
He added: "We now know they came from An Garda Síochána itself".
Yesterday, Garda Commissioner Drew Harris told the Oireachtas Justice Committee that Fiosrú, the Office of the Police Ombudsman, had examined an investigation file into the incident.
Mr Harris said that no issue had been found in relation to garda use of a controlled delivery in relation to alleged firearms offences.
"How could the Department of Justice confirm in writing to a member of the media that the issue in relation to Evan Fitzgerald's tragic case was referred to Fiosrú on 10 May, and the Minister couldn't comment because of that?" Deputy Kelly asked the Taoiseach in the Dáil today.
"But yet, the Commissioner yesterday, in the Justice Committee said he referred it on 18 to 19 May," the deputy added.
"How could it be that the reports from the Irish Times, all other media, said that, when the judge, Judge Zaidan asked what was the provenance of the guns, the garda said, 'investigations are ongoing' into who sold the guns?"
At that point, his microphone was cut off, and the Ceann Comhairle Verona Murphy accused Deputy Kelly of taking "complete advantage" of the house, which she said was "completely unacceptable".
Micheál Martin responded: "The events in Carlow were very traumatic for everyone involved, for the wider community and the family of Evan Fitzgerald, a young man whose life is no longer, no more. And that is a very sad and traumatic event."
"The minister may have been told - or the Department of Justice - that this was going to Fiosrú.
"If that's the case, you don't comment on it.
"I wouldn't comment on anything if it was heading for an investigation. Just wouldn't. 'Cause that is why you leave things go to investigation. I will ask that the Minister will respond to some of these issues."