Defense witnesses testifying in the trial of a 13-year-old boy who killed another boy at a Michigan playground say he's had a rough childhood and is a victim of abuse.

The teen's stepfather told a Kent County jury on Wednesday that he would beat the boy with a belt if he misbehaved.

The 13-year-old is charged with murder in the fatal stabbing last summer of 9-year-old Michael Connor Verkerke at a Kentwood playground, near Grand Rapids. There's no dispute that he did it, although defense attorney Charles Boekeloo says he was deeply troubled and insane.

The Associated Press isn't naming the defendant because of his age. He was 12 at the time.

Social worker Sarah Benjamin says the teen attempted suicide in the juvenile detention center.