PHOENIX -- Renowned forensic psychiatrist Dr. Steven Pitt talks to Mike Watkiss about Saturday's mass shooting at Rep. Gabrielle Giffords "Congress on Your Corner" event in Tucson.
"This is not a 'whodunit,'" Pitt said. "It's a why did he do it, and, more specifically, why did he do it now?
"Based on what we know right now, you're dealing with someone who is disaffected, angry, and a coward," he said "Beyond that, I think it is really, really difficult to come to any definitive conclusions based on Facebook postings or YouTube rantings.
"Hands down, you're going to be looking at a potential mental defense. In the spirit of getting to the bottom of this, to the truth, you're going to have to work very, very hard to uncover everything you can about this individual's thoughts and behaviors during the days, weeks and hours leading up to the commission of the offense."