BELLEFONTAINE, Ohio (AP) — An Ohio man imprisoned for severely beating his infant son in 2007 has been sentenced to more prison time after the boy died in his sleep years later.

The Columbus Dispatch (

) reports Michael Robinson pleaded guilty to involuntary manslaughter and received a sentence that would keep him imprisoned until 2028, when he’d be 65.

A coroner said injuries caused by the Bellefontaine (behl-FOWN’-tihn) man led to his son’s death. The boy suffered brain damage and physical disabilities and died in 2015, at age 9.

Robinson briefly apologized in court Monday, saying he was sorry and didn’t know what else to say.

He had been charged with murder, but a paperwork problem and a lost file weakened the case and led to his plea deal on the lesser charge.

Information from: The Columbus Dispatch,