Story highlights A 12-year-old boy has been charged with murder in the Michigan stabbing death

Prosecutor says he doesn't have a motive; the boys didn't know each other

Police say the 12-year-old ran from the park after the stabbing and called 911

Expert describes the repeated stabbing as "a very personal and very angry act"

A family is grieving and a Michigan community is in shock after a 9-year-old boy was stabbed to death at a playground in his neighborhood this week.

The shock felt in Kentwood, just outside of Grand Rapids, is as much over the sudden and senseless loss of Michael Conner Verkerke as it is over the circumstances of his death: The person accused of stabbing him was a 12-year-old he had just met at the playground.

Conner was playing with three other children Monday "when one of the children, for an unknown reason, pulled out a knife and repeatedly stabbed one of the other children," a Kentwood Police Department statement said.

Police say the attacker is 12-year-old Jamarion Lawhorn. A motive, if there is one, is unknown at this point, as the boys were not acquainted, according to Kent County Prosecutor Chris Becker.

Lawhorn was charged Tuesday with murder. Though he'll be tried in a juvenile court, it will be as an adult, according to Becker, who added that his office has not yet decided whether the murder charges will be first or second degree.

Charles Boekeloo, Lawhorn's court-appointed attorney, said he met his client for the first time at his arraignment Tuesday but had no further comment. Boekeloo entered a not guilty plea on the youth's behalf.

Police said that after he was stabbed, Conner managed to run back home before he collapsed on the porch. An ambulance rushed him to a hospital, where he died Monday night.

Lawhorn, meanwhile, "left the playground then went to a nearby residence where he asked to use the phone," Kentwood Chief of Police Thomas Hillen said.

"I thought he was calling for his parents to come pick him up," homeowner Glen Stacy told CNN. He wasn't. "He called 911," he said.

Stacy described Lawhorn as "calm and collected" throughout, and that he told the 911 dispatcher, "Hi, I just stabbed someone, please pick me up and come kill me, I want to end my life."

The boy then calmly handed back the phone with the operator still on the line, according to Stacy, and they waited for police to arrive. "At no point did I feel threatened," he said.

Stacy said that when the first officers arrived on the scene, they ran toward the playground, which was in the opposite direction. That prompted Lawhorn to raise his voice for the first time, according to Stacy.

"Hey! I'm over here!" Stacy said he shouted. "Let's do this. I'm ready," he said as he walked toward them with his hands on his head, Stacy said.

A competency hearing will be held soon, according to police, but Becker has already predicted an outcome: "My gut tells me they will go for an insanity plea," he said.

One expert said that based on the circumstances and violent nature of the act, it would appear Lawhorn -- who turned 12 in March -- suffers from mental illness.

"The instrument in this case says something about his state of mind," said Dr. Charles Williams, a child psychotherapist at Drexel University in Philadelphia. "It's easy to pick up a gun and shoot someone, but to stab someone repeatedly with a knife -- that's a very personal and very angry act from a psychological standpoint."

In Kentwood, a GoFundMe page was established Tuesday to pay for Conner's funeral. By Wednesday evening, 166 people donated more than $7,000 for the cause.

Lawhorn is being held at the Kent County Detention Center. A preliminary hearing has been scheduled for August 13.