Retired FBI agent Thomas Michael Martens has admitted in court that he never liked his son-in-law Jason Corbett.

Mr Martens wept in the stand as he described how hit the Limerick man repeatedly with a metal baseball bat.

He said he continued hitting him until he was certain he was no longer a threat to either himself or his daughter.

Both Mr Martens and his daughter Molly Martens Corbett deny a charge of second degree murder charge - insisting they acted in self defence.

Journalist Ralph Riegel, who is in Lexington, North Carolina for the trial, said Mr Martens made no secret of the fact that he disliked his son-in-law.

“He said he considered that Jason Corbett was rude; he said that he felt that he was controlling of his daughter,” he said.

“At one point however, he said he could not remember a comment that he made to a work colleague when asked if he was going on a combined family holiday to Washington.

The colleague has claimed Mr Martens said: “why would I want to go on vacation with that asshole.”

Mr Riegel said Friday was “certainly the most dramatic day of the trial so far” adding that Mr Martens became very emotional within minutes of taking to the stand.

“He was effectively saying that he struck his son-in-law Jason Corbett with a metal baseball bat to protect himself and to protect his daughter,” he said.

“He said he was convinced that if he had left the bedroom, his daughter would have been killed and he also feared for his own life.”

Mr Martens rejected claims that he was attempting to take the blame for killing on his daughter’s behalf and denied that the pair had worked together to murder an “unarmed, injured, helpless and naked man as he lay face-down on the bedroom carpet.”

Mr Riegel said that the jury could now be charged to consider a verdict as early as Monday evening or Tuesday.

The trial resumes on Monday morning.