A Louisiana father accused of cutting off the head of his disabled 7-year-old son has been ruled not guilty by reason of insanity, his defense attorney said Friday.

Kerry Cuccia said the ruling by state District Judge John LeBlanc came Friday in the case against 32-year-old Jeremiah Wright of Thibodaux.

Cuccia says Wright will be returned to the state mental hospital in Jackson where he had been held.

Wright has been in custody since August 2011, when Jori Lirette was killed and his head left in the yard of the home Wright was sharing with Lirette's mother, Jesslyn Lirette. The boy required around-the-clock care and was fed through a tube.

Cuccia says prosecutors agreed to the ruling.

A call seeking comment from District Attorney Cam Morvant was not immediately returned.

Wright faced a first-degree murder charge in the Aug. 14, 2011, death. The boy's head was found in the driveway of the home. His other body parts were found in nearby trash bags.

According to a sworn police statement, Wright told investigators he had recently seen signs that made him believe he was living with a CPR dummy rather than his son.

Those signs, he said, included being defecated and urinated on the morning he decapitated and dismembered the boy, whom he referred to throughout the statement as "the dummy."

He also told police he and Jesslyn Lirette had fought the evening before, and that she had told him she was moving him out of the house.