A Piscataway man convicted of shooting and killing his own father – who was a police officer and school board member – was sentenced Thursday to 24 years in prison.

John Mahoney, 27, shot his father, Jerry Mahoney, 49, three times while he slept in a recliner on the morning of Dec. 27, 2007.

Although Mahoney initially changed his story about what happened several times, his attorney argued at trial that he was the victim of an abusive father.

Mahoney, who was 19 at the time of the slaying, found somewhat sympathetic ears with the jury.

Although the jury convicted him of aggravated manslaughter, they acquitted him of the more serious murder charge and urged the judge to be lenient and order that he receive therapy. An appellate court panel in February, however, ruled that a judge should not consider jurors' testimony in sentencing.

During the eight-week trial, prosecutors pushed back against the self-defense claim, saying Mahoney had long planed to kill his father and had spoken to friends about wanting to hire a hit man.

After shooting his father, Mahoney then shot himself in the arm in order to claim that a robber had broken into the home, prosecutors said. He later changed his story to say that he had accidentally shot his father.

The Middlesex County jury in March convicted him of aggravated manslaughter, hindering his own apprehension by lying to investigators, and possession of a weapon for an unlawful purpose.

Superior Court Judge Michael A. Toto, sitting in New Brunswick, handed down a 20-year sentence for the manslaughter charge, for which Mahoney must serve at least 85 percent before becoming eligible for parole. Toto also sentenced Mahoney to an additional four years for the hindering conviction.