(NBCCHICAGO) — A Northwest Indiana teacher was placed on leave after he wrote a threatening message on the chalkboard last week during class, the schools superintendent said.

Lake Station Schools Supt. Dan DeHaven confirmed an Edison Junior-Senior High School teacher wrote a message that read: A) You are idiots!!!!!!!! B) The guns are loaded!!! C) Care to try me ?????????”

Students snapped a photo of the message during first period Friday and posted it on Facebook, DeHaven said. The school resource officer saw the photo on Facebook, and the teacher was sent home by 10:30 a.m. that day.

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