CHICAGO (CBS) — A 20-year-old man accused of opening fire last year at a northern Illinois high school has been declared fit to stand trial.

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Matthew Milby Jr. had been found unfit for trial in March, but that order was reversed after he underwent months of mental health treatment.

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The shooting happened during graduation practice at Dixon High School. It ended when a school resource officer shot and wounded Milby.

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No one else was hurt.