The Fianna Fáil leader says there were general rumours about Maurice McCabe circulating in Leinster House in 2014.
Micheál Martin is the latest witness to give evidence before the Disclosures Tribunal, which is investigating if senior gardaí made allegations to smear the Garda whistleblower.
Deputy Martin told the tribunal there were general rumours about Maurice McCabe circulating in 2014 in political and media circles.
He said there was an air of ‘be careful’, and that he wasn’t dealing with a person who was reliable.
He said an allegation of sexual abuse - which was false - was 'floating in the ether'.
The Fianna Fáil leader said he had met Maurice McCabe, and he was taken by him in the first meeting.
He said what the Garda whistleblower was saying about allegations within the gardaí wasn’t all bluster or talk – he had detail and was meticulous with chapter and verse.
Deputy Martin said he felt this guy should be believed, and what he was saying was correct and stood up.
The Fianna Fáil leader said he also met Ms D - who was concerned her original complaint about Maurice McCabe hadn’t been investigated properly.