September 28 Bomb Threat

Today, a little after noon, a teacher called to say there was a message written in a stairway. The message was a bomb threat. Immediately, I called our SRO officers Jeremy Slight and Becky Stieber and assembled the custodians and assistant principals. We developed a plan.
In less than an hour, we knew who had written the message.
Events like this, which are all too common, leave me wondering. What is it that makes a sixteen year old want to threaten a school-full of students? What types of interventions could we implement to make our students more safe from threats without unreasonably limiting the freedoms of the other 1500 kids?