It was inappropriate for former garda commissioner Martin Callinan to draft a response for Gerald Kean after whistleblower Sgt Maurice McCabe complained about defamatory comments the solicitor made on an RTE programme, the Charleton tribunal has heard.
The tribunal is looking at allegations that senior gardaí were smearing the whistleblower to politicians, journalists and others.
Det. Supt Frank Walsh, who worked as private secretary to the commissioner, met with Mr Kean on 12 February 2014, two weeks after Mr Kean criticised Sgt McCabe on the Marian Finucane show.
Det. Supt Walsh said he had "a good professional working relationship" with Mr Callinan, and that the commissioner was a hard worker, in the office daily from around 7am until late in the evening.
The tribunal heard that the letter from Mr Kean, which enclosed a copy of the complaint from Sgt McCabe, along with handwritten and typed copies of a draft response prepared by Mr Callinan, were not added to the file on Sgt McCabe kept at Garda HQ.
Det. Supt Walsh met with Mr Kean and conveyed the draft response to him, and four paragraphs from the draft were included in the reply which Mr Kean sent to Sgt McCabe, the tribunal was told. No letter was sent by post to Mr Kean.
"Somebody looking at this might think it was a matter that was being swept under the carpet so nobody could see what happened," tribunal barrister Patrick Marrinan SC said.
Det. Supt Walsh said this was not the case.
Det. Supt Walsh said he was not aware that Mr Kean and Mr Callinan had spoken before the solicitor appeared on the Marian Finucane show. The programme aired shortly after Mr Callinan had appeared before the Dáil public accounts committee to answer questions about penalty points cancellations.
Tribunal chairman Mr Justice Peter Charleton said it was "really really really strange" that the commissioner would prepare a draft letter in a private matter between two citizens.
Det. Supt Walsh said Mr Callinan expressed his view that the matter was inappropriate for him to reply to, but was anxious to do something for Mr Kean, who was supportive of An Garda Siochana.
Det. Supt Walsh said his meeting with Mr Kean was not "clandestine", and the fact the letters were before the tribunal showed there was no attempt to hide them.
"The fact it is before us today shows it was never meant to be covert," Det Supt Walsh said.
"The commissioner never told us. You never told us. Mr Kean never told us. It took counsel rooting through tens of thousands of documents to find it," the tribunal chairman said.
"The documents were kept in the commissioner's office but I don't know which file they were on," Det Supt Walsh said.
The tribunal has adjourned and will resume on April 30.