The shooter was another transgender psycho, born biologically as a woman, but self-identified as he/him. It shot out a side door to enter the school. According to a fellow poster on the Tennessee Gun Owners forum whose wife works at the school, the school does practice active shooter drills. Apparently, the shooter did leave a manifesto. I imagine this is related to the recent Tennessee laws that ban transgender events where children are present, and a law that limits gender alteration surgery for minors.
Personally, I see people are born either genetically male or female, with the rare occasion of a hermaphrodite, which has both sexual organs. No amount of hormones or drugs are going to change a person's biological sex. It's time for American society to stop coddling these "transgender" people and go back to treating them as mentally ill. I worked with someone that was "transgendered" and we were threatened with firing if we failed to address this person with their preferred pronouns. There are times when I look around and think, "Am I the only one who is sane here?" I see some of the world sports administrating bodies are starting to exclude transgender males from competing with true women. However, you have Biden and Time Magazine giving women awards to transgenders. I would think that at some point women are going to stand up and point out the biological differences between a transgender and a woman. But wait... we have a Supreme Court Judge who can't even define a woman, a question that ironically was generated by Tennessee Senator Blackburn.
Seeing that this shooting occurred in Tennessee, I suspect we'll see State legislation generated quickly to allow school personnel to be armed.