Reportedly someone heard a bolt slam shut on campus and thought they saw the barrel of a gun they thought was an AK-47 in the bathroom. They ran, pulled the fire alarm, and that part of campus was quarantined. No shots or anything, official story about whatever happened still pending.
Given that I suspect 1/3 to 1/2 of the people at the school probably have shotguns or hunting rifles in their cars, an attack on said school seems rather ill conceived.
Further details when they're available, to determine if this is legit or not.