Tom and Molly Martens will remain in a US prison until next summer.
Prison authorities in North Carolina have admitted a mistake was made when calculating their sentences.
Molly Martens, and her father Tom, were convicted last month of the manslaughter of her husband and his son-in-law, Jason Corbett.
The Limerick father-of-two was beaten to death at his home in North Carolina in 2015.
On Monday, prison authorities revealed the father and daughter were due for release next week, sparking an outcry from Mr. Corbett's family.
However, it's now been confirmed to have been a mistake, and the correct calculation of the Marten's sentences mean neither will be released from jail until next year.
The Department of Adult Corrections in North Carolina says that after reviewing the initial projected release dates they were found to be wrong, and the correct date is June 27th 2024.