TRENTON, Mich. -

A federal jury has convicted a man on explosives charges for faking a Middle Eastern accent when he called in a bomb threat to a suburban Detroit high school and placed at least two explosives in the area.

The jury in Ann Arbor found 42-year-old ex-convict John R. Kennedy of Trenton guilty Wednesday of making and possessing explosives.

Detroit U.S. attorney spokeswoman Gina Balaya says the crimes happened in April 2011.

She says Kennedy disguised his voice "in a Middle Eastern accent" and "telephoned a bomb threat to Trenton High School."

His call warned that four bombs would explode inside the school within an hour.

Balaya says a teacher found an explosive in a parking lot.

The next day, Balaya says Kennedy exploded another device outside a store.

Sentencing is March 5.

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