The death of Jason Corbett's first wife is set to be entered into evidence as part of a sentencing hearing for Molly Martens.
Ms Martens and her father Tom Martens have accepted a plea deal of voluntary manslaughter of the Limerick man in the US.
Mr Martens pleaded guilty to voluntary manslaughter, while his daughter entered a "no contest plea", meaning she accepted the charge without an explicit admission of guilt.
In return for their plea, the State of North Carolina has dropped the murder charges against the father and daughter.
Jason Corbett (39) was beaten to death with a baseball bat and a concrete paving slab in his Lexington home in 2015.
He had moved to the United States with his two children in 2011 after marrying Ms Martens, who had been the children's nanny.
Jason CorbettMs Martens and Mr Martens were convicted of murder in 2017 but were allowed a retrial after US courts ruled that certain evidence had been excluded.
Irish Independent Southern Correspondent Ralph Riegel told The Pat Kenny Show Ms Martens' legal team is looking to introduce the death of Mr Corbett's first wife, who died from an asthma attack, into court.
"Her solicitor Douglas Kingsbury has said they will enter evidence as regards the circumstances of the death in November 2006 of Mr Corbett's first wife," he said.
"I think that's going to be a major issue in this sentencing hearing.
"What is important is not so much what Mr Kingsbury said yesterday but what he didn't say.
"He did not say that Jason Corbett's first wife was actually with her sister when the asthma attack happened.
"He did not say that Jason Corbett, in a desperate attempt to save his wife, had put her in his car and driven towards an ambulance that was coming to their aid from University Hospital Limerick.
"He also didn't say that Jason had actually revived his wife in the car... and that she actually died in the ambulance as she was being brought to UHL."
'Extreme levels of violence'
Mr Riegel said the plea deal for the Martens is on the lower end of the manslaughter scale.
"The sentencing can range from as little as parole in a case where there are extraordinary mitigating circumstances, right up to almost 17 years" he said.
"The judge was at pains to say yesterday that only repeat offenders with long criminal histories would qualify for a sentence of the order of 17 years.
"He said that does not apply in either the case of Tom Martens or Molly Martens."
Mr Riegel said there were extreme levels of violence used against Mr Corbett.
"Both Tom and Molly Martens and their defence teams... they have said that both acted entirely in self-defence," he said.
"Mr Martens legal team said he accepted that, in the extraordinary circumstances of what happened, he went too far.
"That's why he has pleaded to voluntary manslaughter.
"They're setting out what they're describing as a large number of mitigating circumstances to explain what had happened on the night."
'Totally uninjured'
Mr Riegel said a lack of injuries on either Tom and Molly Martens will also be scrutinised.
"Mr Martens said that he heard a noise upstairs, he was in the guest bedroom downstairs with his wife Sharon," he said.
"When he went up to investigate he said he saw his Irish son-in-law effectively strangling or holding his daughter by the neck, and he intervened to protect her and then to protect himself.
"Both were found totally uninjured at the scene.
"That's going to be one of the central arguments over the next couple of days about whether they were uninjured, as the police and the State has argued, and the general circumstances of how Mr Corbett came to suffer his fatal injuries," he added.
