GRAND RAPIDS (WWJ/AP) – The stepfather of a 13-year-old boy who killed another boy at a park said Wednesday that he beat the teen with a belt, testimony that was intended to reinforce an insanity defense during the murder trial.

There is no dispute that Jamarion Lawhorn stabbed 9-year-old Michael Connor Verkerke last summer at a Kentwood playground, near Grand Rapids. But defense attorney Charles Boekeloo is arguing that the teen’s awful childhood made him insane and not criminally responsible.

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“I didn’t whoop him all the time, only if he did something bad. … I left the marks on him, I apologized and I never used corporal punishment again,” the stepfather told jurors on the second day of the trial in Kent County court.

Lawhorn, who was 12 at the time, is designated as an adult in the juvenile court system. That means he would be sentenced as a juvenile if convicted, then resentenced as an adult at age 21.

Social worker Sarah Benjamin said Lawhorn tried to kill himself at the juvenile detention center while the murder case was pending. A psychiatrist told jurors that he was given medication for depression.

Prosecutors have said the teen planned to stab someone for a year and hid a knife in a sandbox.

Mental health experts are expected to testify Thursday as the trial nears an end.

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The victim, called “Connor” by his family, was stabbed to death Aug. 4, 2014, after falling off a slide. The two boys didn’t know each other before the younger boy was approached at the playground.

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.”

According to a court filing, Lawhorn told investigators he stabbed Verkerke because he wanted to go to jail, that he is “bad and always does stupid things,” and that he thought he’d be killed “for doing something like this.”

Lawhorn’s parents have been charged with child abuse, which authorities believe may have contributed to the boy’s mental state, and, in turn, the stabbing. Records showed that he had been living in a volatile home that was described as “deplorable” by child welfare workers.

WWJ is identifying Lawhorn, who turned 12 in March, because he is charged as an adult.

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