Racism is alive and well...
If they truly thought it was a bomb, why didn't they evacuate the school, or why did they send the clock with the cop and the kid back to the station?
The alarm went off in class, that's how the teacher learned of it. If it was a bomb, that would be explosion time, right? C'mob people, before you make texas look even worse, think about your responses. Common sense seems to be less and less common these days.