He thinks he's the joker, according to the news. He had red hair and claimed to be reenacting a screen from the 2008 film the dark knight.
I don't know how much I believe this. This guy was a neuroscience major. Either he completely snapped very recently or he's completely trolling this investigation, possibly to set himself up for an insanity plea.
I read an article where they contacted the parents and the mother literally said that she was not surprised.

Good job raising a maniac and sending him out into society.