It has been sourced that the shooter was Jared Lee Loughner. Here is his youtube channel. It appears he suffered from paranoid delusions. He was likely motivated by paranoid right wing hate speech. There is really not a lot more concrete info I can find at the moment.
It seems clear from his youtube channel that he suffered some form of mental disease. I suspect he was whipped into action by hate speech and this is the reason that I support hate speech legislation. Every time the free speech vs. hate speech debate comes up around here I get attacked for my support of hate speech laws like the ones we have here in Canada.
Anyway, this tragedy will likely result in a lot of debate on this topic.
Sorry I won't be able to participate more in this diary, guests have just arrived.