GRAND RAPIDS (WWJ/AP) – An official says a 13-year-old boy who fatally stabbed another boy at a playground in western Michigan has shown progress while held in a juvenile detention facility.

Kent County probation officer Dan Cory on Tuesday gave an update to a judge in Grand Rapids, saying Jamarion Lawhorn is “doing well” but suffers post-traumatic stress disorder after being raised in an abusive home and had periodic “outbursts” at the facility in Evart.

READ MORE: Kellogg's Being Sued Over Strawberry Pop-Tarts

There was no dispute that Lawhorn, who was 12 in 2014, killed 9-year-old Michael Connor Verkerke at a playground in Kentwood. The defense argued that years of abuse at home had ruined Lawhorn’s mental health, but the jury convicted him last year of first-degree murder.

If Lawhorn meets expectations, he could be released at 21, although prosecutors could seek a prison term at that age, too.

Following his arrest, Lawhorn told police that he was “fed up with life” in his abusive home and wanted to be locked up for life or given the death penalty. The two boys didn’t know each other before Lawhorn approached Verkerke at the playground, investigators said.

READ MORE: Target To Open Store In Midtown Detroit

Lawhorn has been described as behaving “very calmly” after the stabbing. Witnesses said the boy mentioned that he was upset because nobody loved him, and that he had taken multiple pills earlier in the day. After the stabbing, a neighbor told police that the boy said, “I want to die. I don’t want to be on this earth anymore.”

His parents, Anita Lawhorn and Bernard Harrold, were both sentenced to one year in jail and five years probation for third-degree child abuse involving their son.

WWJ is identifying Lawhorn because he was charged as an adult.

MORE NEWS: City of Hamtramck To Handout Water Filters On Oct.26

TM and © Copyright 2016 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2016 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.