A man serving decades in prison for conspiring with his daughter to kill her ex-husband in one of New Jersey's most notorious murder cases lost a bid to withdraw his guilty plea on Monday.

Thomas Dorsett pleaded guilty to murder and arson for hire in the 2010 death of Stephen Moore. He admitted bludgeoning and strangling Moore behind the family’s house after Moore arrived to drop off the couple’s young daughter, then hiring someone to set Moore's mother's car on fire with Moore's body in the trunk. Prosecutors said Dorsett wound up torching the car himself.

Kathleen Dorsett, a former elementary school teacher, also pleaded guilty in Moore's death. She and her mother admitted trying to hire a hit man to kill Moore’s mother to stop her from testifying against them and keep her from getting custody of the girl.

Kathleen Dorsett was sentenced in 2013 to 58 years in prison and Lesley Dorsett received a seven-year sentence. Thomas Dorsett was sentenced to 45 years.

Prosecutors said the plot grew out of the couple’s failed marriage and an acrimonious divorce that led to a custody battle over their daughter.

On Monday an appeals court rejected Thomas Dorsett’s argument that he received ineffective assistance from his attorney when he negotiated his plea deal. His guilty plea was a condition for his wife to make her own guilty plea and receive a much shorter sentence than she could potentially have received if she had gone to trial, according to Monday's ruling.

John Pieroni, an attorney who argued on behalf of Thomas Dorsett, said Monday he was disappointed with the ruling and said he had primarily been attempting to get an evidentiary hearing to address issues with Dorsett's former attorney.