The document, which was revealed yesterday at the tribunal, was given as briefing material to legal counsel representing Ms O’Sullivan and four senior officers at the O’Higgins commission in 2015.
The O’Higgins inquiry was investigating allegations by Sgt McCabe of poor policing in Cavan/Monaghan and allegations of corruption and malpractice against senior officers.
At the start of yesterday’s proceedings, Michael McDowell, counsel for Sgt McCabe, expressed his concern at the circulation of a new document by lawyers representing Garda counsel at O’Higgins — Colm Smyth SC, Garret Byrne BL, and Michael MacNamara BL.
He said the four-page document, apparently extracts from a 2011 unpublished internal garda investigation report, known as the Byrne/McGinn report, into Sgt McCabe’s complaints had not been seen by either him or his client before.
Mr McDowell described its contents as “fairly shocking” and “highly damaging and offensive” to his client, alleging he was a “paranoiac”.
It said Sgt McCabe had “lost control” as sergeant in charge of Bailieboro Garda Station and that he should not be put back into it.
Mr McDowell said the document only emerged after Nóirín O’Sullivan had finished giving evidence on Wednesday.
He said it was “very likely” that she was aware of it and claimed that this “utterly changes the absolutely anodyne and hands off” responses she gave to his questions.
He said Ms O’Sullivan had led the tribunal to believe that the source of information to her counsel regarding Sgt McCabe had come from three senior officers, Chief Supt Colm Rooney, Supt Michael Clancy and Supt Noel Cunningham.
“I am doubting the veracity of what I was told that counsel for the commission were entirely dependent on what three people told them,” said Mr McDowell.
He said he would have questioned Ms O’Sullivan about the document.
“I’d like to have her back and ask her about this,” he said.
Tribunal chair Mr Justice Peter Charleton said it may be necessary for Ms O’Sullivan to return and that if Mr McDowell wished to make an application in this regard he would “consider it in due course”.
Mr Smyth said he did not see nor use the document.
Mr Smyth later said that a legal document given to the O’Higgins inquiry on May 18, 2015 — which mistakenly stated that Sgt McCabe had made a complaint against, rather than to, a superintendent in a bid to get the release of full DPP directions in a case — and his putting this mistake to Sgt McCabe at the commission, was not accurate and it was the fault of his clients.
“It was done on explicit instructions of client, who got it wrong,” he said.
Mr Smyth gave a robust defence of the strategy to challenge Sgt McCabe’s motivation and credibility, including during what were often testy exchanges with Mr McDowell.