Why Meadow Died: The People and Policies That Created The Parkland Shooter and Endanger Americas Students
https://www.amazon.com/Why-Meadow-Died-Policies-Parkland/dp/1642932191
Great book, very well footnoted. Short answer is really stupid Leftist policies, some or all of which are likely in place in your locale. This kid was a known wolf for years, but nothing was done to help him and separate him from the rest of the students.