The Court of Criminal Appeal has rejected an appeal by Linda Mulhall against a 15-year prison sentence for her part in the killing of Fareh Swaleh Noor in 2005.
The 32-year-old mother of four had claimed the trial judge did not have access to crucial psychiatric and probation reports when he sentenced her for manslaughter.
The court heard that these reports showed how Mulhall had had every conceivable level of brutality visited upon her from an early age leading to relationship and addiction problems later in life.
Probation reports indicated she had shown deep remorse for her part in the killing of Mr Noor.
However the appeal court ruled that the trial judge, Mr Justice Paul Carney, had correctly considered the evidence to be at the very serious end of the scale.
He had considered the appropriate sentence should fall between 18 to 20 years but had discounted some of those years because of her cooperation with gardaí and her previous clean record.
The court also rejected an application to have a rehabilitation programme built into Mulhall's sentence.
Linda Mulhall was convicted of manslaughter and her sister Charlotte is serving a life sentence for the murder of Mr Noor in March 2005.
His headless and limbless body was found in the Royal Canal in Dublin.
Some parts of his body have never been recovered.