Molly Martens, aged 33, and her father Thomas Martens, aged 67, a former FBI agent, were convicted of Mr Corbett’s second-degree murder by a jury last week after a month-long trial.
Mr Corbett, a father of two, was beaten to death with a paving stone, which was on his wife’s nightstand in their bedroom, and an aluminium baseball bat in his home in Panther Creek Court, Wallburg, North Carolina, in the early hours of August 2, 2015.
Both were sentenced to 20-25 years in prison for second- degree murder, or murder which was not premeditated.
Speaking for the first time since the conviction, Mr Corbett’s brother John, who lives in England, said the family’s suffering is set to continue as an appeal is likely to be lodged.
“I personally feel they should have been charged with capital one [first-degree murder] and should have got the death penalty,” he told the Limerick Leader. “They continue to show no remorse. I wish them eternal pain and suffering in prison.
“But we, as a very close family, can now find some form of closure and comfort knowing Molly Martens and Thomas Martens are in prison where they belong.
“We will finally mourn Jason and let him rest in peace with his beloved [first] wife Mags. We will continue to grow stronger in our integrity and love for each other, but we will never forget the Martens as a stain on society.”
John, one of five brothers of the deceased, from Janesboro, Limerick City, urged people not to donate to the fund set up by the Martens family to raise $300,000 towards their legal costs, particularly for an appeal over what they claim was a “wrongful conviction”.
Mr Corbett said those who donate to it “are condoning cold, calculating murder and do not respect the law of the land in the US, and do not deserve to be called US citizens”.
“They should donate their money to the relatives of murder victims in North Carolina,” he said, adding that his brother died at the hands of “cold, unapologetic killers” and they would not wish what they have endured over the past two years on any family.
“From day one they have shown no remorse,” he said.
Calls by the public to shut down the fundraising campaign have been rejected. The moderators of the GoGetFunding page have been flooded with complaints.
Mr Corbett praised his “wonderful family who endured all the horror in the court for four weeks, yet held their dignity and composure in the face of pure evil”.
In the event of an appeal, he said he hopes that the US justice system continues to see “through their total remorseless lies”.
He described his youngest brother Jason, who was born 15 minutes after his twin brother Wayne in February 1976, as a “6ft 2in teddy bear, who wouldn’t hurt a fly”.
He said Molly Martens “always seemed a bit distant” to him when she arrived into their lives to work as an au pair for the children, following the death of Jason’s first wife, Mags Fitzpatrick, from an asthma attack in 2006.
“Most of the family advised him not to go to America and marry her,” said Mr Corbett.