The Charleton tribunal is examining claims that allegations of sexual abuse were used as part of a campaign to smear and undermine the reputation of Sgt McCabe.
Kay McLoughlin, a social work team leader, sent the letter to the sergeant seeking to meet with him to discuss the allegations. The letter incorrectly contained false allegations that Sgt McCabe “digitally penetrated” a child, know as Ms D, and threatened her father.
Tribunal chairman Mr Justice Peter Charleton asked Ms McLoughlin if she “was in some way a puppet of the gardaí”.
Ms McLoughlin said: “No, I have a duty to my clients. If I felt I was in some way biased or even acquainted with someone I wouldn’t deal with the case.”
Ms McLoughlin agreed with Conor Dignam, for the Garda Commissioner, that high staff turnover could have led to problems dealing with the Tusla file on Sgt McCabe.
Four people held the post of social work team leader between July 2013 and July 2014, when Ms McLoughlin took over in the role.
Ms McLoughlin said that, before she took over, she was aware of Sgt McCabe from media reports.
A Tusla file on Sgt McCabe was opened when Ms D sought counselling in 2013 about a previously reported allegation which was investigated by gardaí in 2006. The DPP decided against pressing charges in the case due to lack of evidence in 2007.
An administrative error led to false allegations from an unrelated case being added to Sgt McCabe’s file.
In January 2016, solicitors for Sgt McCabe wrote to Tusla after he received the letter written by Ms McLoughlin containing the false allegations.
On day nine of the inquiry, Diarmaid McGuinness, for the tribunal, asked Ms McLoughlin if the errors in the file were created and perpetuated in-house.
She said they were and add ed that they had “absolutely nothing to do with gardaí”.
Ms McLoughlin reviewed the files in late 2015, but said she did not see an email in the file outlining how the allegation of “digital penetration” from an unrelated case had been added to the file.
Mr McGuinness said the false allegation was repeated in six documents in the file in 2014, and that of the remaining 19 documents, a number were devoted to correcting the error, including an email from social worker team leader Eileen Argue outlining how it occurred.
Ms McLoughlin said she accepted she had missed a crucial piece of information. “I did not review the file fully. I had no cause to know an error had been made in it,” she said.
“I failed to appreciate that there was a significant error on the file and I failed to review the file thoroughly.”
Ms McLoughlin said she was aware of Sgt McCabe. She said she assumed Ms D might have sought counselling in 2013 because “Mr McCabe’s name being in the media may have triggered something for her”.
Asked if she or anyone else in her department were “out to get” Sgt McCabe, Ms McLoughlin replied: “Absolutely not.”
She said if she had followed through and arranged a meeting with Ms D, or read the file fully, a letter sent to Sgt McCabe at the end of 2015 would never have been issued.
“I fully accept that letter was inappropriate to be sent out. I take responsibility for it,” she said.
After solicitors for Sgt McCabe responded to the letter sent to the sergeant, Ms McLoughlin said she realised she had made a “grave error”.
The tribunal continues.