HARRISBURG, Pa. (AP) — A central Pennsylvania man has been sentenced to at least four years in prison for the death of his son, who was found unresponsive in a bathtub two years ago.

Twenty-two-year-old Stephen Dixon denied at Thursday’s sentencing that he killed his son, Jayahn Cox-Phoenix. He had pleaded guilty to charges of involuntary manslaughter, aggravated assault and child endangerment.

READ MORE: Eastern State Penitentiary To Resume Night Tours Next Month

The boy was taken off life support on his third birthday after being found unresponsive in the tub at a Swatara Township, Dauphin County apartment in May 2010.

READ MORE: Sinkhole Slowing Traffic At Schuylkill's King Of Prussia Interchange

Dixon maintains his son drowned in the tub while he was distracted. But investigators believe Dixon beat Jayahn because the boy wet himself then put him in the tub to cover it up.

Dixon could be freed in two years with time served.

MORE NEWS: 6-Year-Old Boy Injured, Father Killed In Southwest Philadelphia Triple Shooting, Police Say

(© Copyright 2012 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)