Garda death had 'devastating effect' on officers in Buncrana, Charleton tribunal told

Mr Devlin said that in March 2011 he learned about the connection between McDermott and Garda Keith Harrison, whose partner Marisa Simms was a sister of McDermott's, a few weeks before McDermott's trial for manslaughter.

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

"It was only a few weeks before the trial. Emotions in the unit were a bit taut at that time with that coming up," Mr Devlin said.

Mr Devlin said that Garda Harrison made an address to gardaí at the station after the connection emerged.

"He in a way maybe was apologising for not disclosing it earlier," Mr Devlin said.

Mr Devlin said that Garda Harrison also told him privately that he was very happy working in Buncrana, and the longer he stayed the more difficult it had become to disclose the connection.

Following the revelation, Garda Harrison was transferred to Donegal town.

Mr Devlin said that Garda Harrison's work was "very good" and he was not aware of him being victimised in any way.

The connection came to light after Garda Harrison reported an incident in Churchill, Co Donegal of alleged domestic violence between his partner Marisa Simms and her ex-husband.

Garda Peter Kearins, who responded to the call in Churchill, said that when he got to the scene, he "didn't believe that threat was as serious as it had been made out to be."

Tribunal chairman Mr Justice Peter Charleton said that there had been "a threat of violence" and gardaí were obliged to respond.

The tribunal resumes tomorrow.