Banning guns, of course. That's actually the most rational thought when the whole situation is taken into consideration. There is, of course, otherwise no motive for such an act. It is not a robbery or a drug deal gone bad, it is a mass execution done by professionals with the intent to shift public opinion. There will be more and more events like this one until the objective is sufficiently achieved or until those in power fall from power.
Black Op Agent goes to victim/"shooter" house, kills someone, kidnaps victim/"shooter", goes to school, shoots children and victim/"shooter", and leaves his corpse to appear as if victim/"shooter" did it all and then killed himself.
Black Op Agent gets picked up by getaway driver, and heads back to HQ, perhaps in a police cruiser dressed as a police officer.
Tune in next time.