A garda whistleblower used the Pulse system over 30 times to look up his partner's details after an anonymous letter led to a HSE inquiry into the welfare of her children, the Charleton tribunal has heard.

Garda Keith Harrison used the garda computer system to check on Marisa Simms in the wake of the anonymous allegations in early 2012.

In its current module, the tribunal is looking at contacts between gardaí and Tusla, the Child and Family Agency, in relation to Garda Harrison.

Retired chief superintendent James Sheridan said that after he received reports of "a multiplicity of checks," he issued a directive on data protection to all officers in the region, and met with Garda Harrison.

"He could not give me any valid reason for conducting the checks on Marisa Simms and he gave me an assurance that he would cease," Mr Sheridan said.

Senior counsel Mark Harty SC for Gda Harrison said that the figure of "over 30" Pulse checks was inaccurate, and at the time in question there were 22 checks, dating from 2007.

He said Garda Harrison made the majority of checks to see who else was making entries relating to Ms Simms, and "he believed at the time that they were under surveillance, both he and Ms Simms.

Asked by the chairman, Mr Justice Peter Charleton if Garda Harrison was under surveillance, Mr Sheridan replied "Absolutely not."

Mr Sheridan said he was asked if he would accept Garda Harrison on transfer to Sligo in February 2011, and was happy to do so as there was a personnel embargo and he welcomed the extra resource. The following month, he learned in a garda bulletin that Garda Harrison was transferring to Buncrana in north Donegal.

Mr Harty said that senior officers in Limerick and Portlaoise had refused to accept Garda Harrison on transfer from Athlone. Mr Sheridan agreed that this was "not commonplace". Mr Sheridan said that in March 2011, he was informed of an incident in Churchill near Letterkenny involving garda Harrison's partner and her ex-husband, as a result of which he met with Garda Harrison.

Garda Harrison had travelled to Churchill in a garda car while off-duty, because of the incident.

Garda Harrison's partner was a sister of Martin McDermott, who was later convicted of the manslaughter of Garda Gary McLoughlin following a high speed car chase. Garda Harrison had not previously informed his superiors that he was in a relationship with the sister of the man facing charges relating to the homicide of a local garda.

Mr Sheridan said that while Sgt Harrison's partner was not in any way responsible for the actions of her brother, he had to "manage the circumstances", and arranged to have Garda Harrison transferred away from Buncrana to Donegal town.

Mr Sheridan said he rejected utterly assertions by Garda Harrison relating to the meeting.

"To say that I was angry or treated him in any way disrespectful (sic) is a gross misrepresentation of how that meeting was conducted," Mr Sheridan said.

Mr Sheridan said he did not threaten to transfer Garda Harrison "down the country" or send him to the Sligo-Leitrim division.

"I did mention to him that he was originally to go to Sligo," Mr Sheridan said. "The homicide of Gda McLoughlin will never be forgotten, and he will always be associated with Buncrana," Mr Sheridan said to Mr Harty.

"I was trying to be as fair as I could be to your client in those circumstances, I deemed it appropriate that he be transferred to Donegal town. There was no malice in my decision."

The tribunal continues.