Molly Martens and her father Tom are set to face a re-trial for the murder of Limerick man Jason Corbett.
The pair were released from jail after being granted bail on Wednesday.
In 2017, they were found guilty of the second-degree murder of 39-year-old Jason Corbett.
He was beaten to death in the bedroom of his North Carolina home with a paving stone and a baseball bat in August 2015.
His wife Molly and her father Tom, a former FBI agent, were found guilty of second-degree murder.
They had served almost four years of a 20 to 25-year jail term when the North Carolina Supreme Court quashed the convictions over evidential issues.
Last week, the Corbett family said they were 'devastated' to learn Molly and Tom Martens had been offered a plea deal by US prosecutors.
It was thought that such a deal, if accepted, would have meant the pair would not have faced a re-trial.
But Ralph Riegel, southern correspondent with the Irish Independent, says the deadline for a plea deal passed with no agreement.
He told Newstalk Breakfast Mr Corbett's family were also considering legal action.
"They were vehemently opposed to a plea bargain deal - the family had said that under a new element of North Carolina law, they would actually take a legal challenge to any plea bargain deal on grounds of perceived leniency.
"There was also a petition launched on their behalf - and that petition attracted enormous attention not only in Ireland, but of course in the United States.
"My understanding is that there was significant contact by members of the public with the District-Attorney's office in Davidson County over any such plea deal.
"The deadline was set for yesterday, and that deadline passed without a plea deal being accepted.
"And it was made very clear yesterday that both Tom and Molly Martens were released on bail pending a re-trial."
He said plans are already in motion on the re-trial.
"So what happens now is the District-Attorney's office is gone into pre-trial mode, and we will hopefully - in the near future - hear details of roughly when that trial is planned".