The tribunal has been provided with a statement which alleges Mr Barrett was told before the commencement of O’Higgins in 2015 that “we are going after Maurice at the commission”.
The tribunal, among other issues, is examining whether there was an attempt to smear the whistleblower at the O’Higgins Commission, which was set up to examine complaints about malpractice within the force.
In the days following the publication of the O’Higgins commission report in 2016, the Irish Examiner reported that there had been an attempt to impugn Sgt McCabe’s character by suggesting his complaints had been motivated by a grudge against a superintendent.
Following the production by Sgt McCabe of a tape recording of a meeting where he was alleged to have expressed the grudge, the matter was not pursued. The matter did not feature in the final commission report.
The suggestion that Sgt McCabe was motivated by a grudge came from the legal team acting for Garda Commissioner Nóirín O’Sullivan.
Once the matter became public, Ms O’Sullivan issued a statement saying she never instructed her legal team to impugn Sgt McCabe’s character, “or to make a case that he was acting maliciously”.
The Charleton Tribunal, which is examining the extent, if any, that Sgt McCabe’s character was smeared is due to hold public hearings on the issues around the O’Higgins Commission next year.
Mr Barrett is expected to give evidence to the effect that he was briefed about “going after” Sgt McCabe.
Mr Barrett is already a central figure in the controversy about the misuse of funds at the Garda college in Templemore. His internal investigation into the issue led ultimately to an audit being conducted and the Oireachtas Public Accounts Committee (PAC) hearings on the matter.
Hearings at the Charleton Tribunal are due to begin on July 4. The tribunal’s first module will examine how a completely false allegation of child sexual abuse against Sgt McCabe was generated in the child and family agency Tusla, and what, if any, role members of An Garda Síochána had in the matter.
Other modules to be heard over the rest of the year include one concerning allegations of harassment by another garda, Kieth Harrison, and whether there was a campaign by garda HQ to smear Sgt McCabe in the media.
Meanwhile, the PAC is to meet privately next Thursday to begin drawing up its report in the Garda college financial scandal.
The report, which is expected to be based heavily on Mr Barrett’s investigations and the PAC’s own public meetings with key officials in recent weeks, is likely to be heavily critical of Ms O’Sullivan among others.