MASSILLON, Ohio (AP) – Police say the seventh-grader who fatally shot himself at school last week had planned a school shooting that would harm others and put that plan on his cellphone.

Jackson Township Police Chief Mark Brink said at a news conference Thursday that the student’s memo on his phone expressed admiration for the Columbine shooters and detailed an eight-step attack plan.

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Authorities say the boy brought a semi-automatic rifle to Jackson Memorial Middle School Feb. 20, along with a backpack containing ammunition, bottle rockets and batteries.

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Authorities say he went to the restroom, where he shot himself in the head. He died the next day.

Brink says police don’t know why Simons changed his mind and killed himself. He says it doesn’t appear anyone had prior knowledge of the boy’s plan.

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