GILLETTE, Wyo. (AP) — A Gillette man convicted of killing his girlfriend's 2-year-old son has been sentenced to life in prison without parole.

Donald Foltz Jr., 36, was sentenced Thursday for the Dec. 30, 2014, death of Braxton Bailey. Foltz was convicted in November of first-degree murder.

Forensic experts testified the boy died of trauma to his abdomen area. Foltz's attorney argued there was no way to prove what caused the trauma.

About a week before his death, Braxton was taken to the hospital after complaining of pain in one of his legs. Charging documents say the doctor raised the possibility of child abuse.

Foltz has a previous child abuse conviction involving a 2-year-old child in Greeley, Colorado.