He conveniently forgot to mention violent movies and violent video games:
The father was an assistant director on a film series - “Hunger Games” - in which the main plot line is teenagers murdering other teenagers.
Also, the self-videos left behind by his murderous son clearly imitates language and plot lines from “American Psycho,” a movie about a man who murders female prostitutes.
Finally, in his son's manifesto, the young man mentions his enjoyment of violent video games.
I'm more interested in whether the kid was on Ritalin or worse psychotropics for the better part of his life. Being the prescription-based equivalent of a cocaine addict from early childhood has probably short-circuited many a young mind:
The killer was only trying to please, or at least impress, his father. "Look over here, Dad, I'm as good as you.
"Why didn't you give me a starring role in your life/movie?"
That about says it all.