As a resident of Chicago; the police force is overwhelmed by the high number of crimes that occur every week. The gangs and criminals get their guns and knives, through illegal means and no laws keep criminal from killing.
This last shooter, broke five laws before he entered the school. All previous shooters, Aurora, CO, Oregon shooter, Timothy McVeigh, etc. all broke laws prior to killing their victims. Only law abiding citizens obey the laws and become victims of the criminals. Until we solve the problem of evil and hate that these people have, will these crimes stop; or an armed citizen willing to protect us and themselves.