My Theory: He was a smart guy. He knew from a young age that something was wrong. He wasn’t as “normal” as other people. He didn’t really fit in so he kept to himself mostly.
His mother and father saw this too but they denied it or hoped he would grow out of it in time. He did great in school and took up Neuroscience to help him figure himself out.
In his early twenties, he began to loose touch with the common reality. This is an age when schizophrenia typically sets in. His delusions gained much more power. The obsessions were too demanding. His performance at school dropped drastically.
He gave up on ever figuring himself out and decided to drop out of the program.
If he was a paranoid schizophrenic, that doesn’t excuse him. He could have asked for help from someone he trusted or someone who loved him. He could have quietly blown out his own brains with the first gun he bought. He was a smart guy.
Instead he followed and embraced his foul delusions. He decided to kill a lot of people. This is the essence of evil. Better that a stone had been tied around his neck and he was cast into the sea.
Your probably correct .
His plotting the attack will be hard to put up a
Mental illness case