A prosecutor on Thursday urged a jury in western Michigan to convict a 13-year-old boy of murder in the fatal stabbing of a younger boy at a playground, saying a childhood of neglect and abuse is not a "free pass to kill."

The teen was 12 when he killed 9-year-old Michael Connor Verkerke last summer in Kentwood, near Grand Rapids. The last day of the trial centered on the defendant's mental health and whether he should be criminally responsible for what happened.

Defense attorney Charles Boekeloo said the boy stabbed Michael because he was desperate.

"He was in a heightened state of fear caused by months and years of abuse," Boekeloo told jurors during closing arguments.

Defense psychiatrist Priya Roa said abuse had harmed the teen's mental health and put him in a "trance-like" state of fear and rage. But Susan Tremonti, a psychiatrist testifying for prosecutors, said he knew what he was doing, even hiding the knife in sand before the attack.

"He could apply rational choice," she said.

The Associated Press isn't naming the boy who's on trial because of his age. If convicted, he would be sentenced as a juvenile, then resentenced as an adult when he turns 21.

Prosecutor Kevin Bramble told jurors that the killing was planned for months and the boy knew what he did was wrong because he called 911. Bramble said many victims of abuse don't kill people.

"They do not get a free pass to kill someone to draw attention to their plight," he said.

The jury will begin deliberations Friday.