Re: Wanna-bes?
I think it quite plausible that there will be a number of incidents from people who are radical Muslim sympathizers, not actually part of Al Quaeda or any other organized group, but want to put their oar in for the cause. Copycats, after a fashion, who may have had other mental problems before 9-11, but have now fixated on the terrorist cause without actually having been in any contact with any known terrorists.
The shooter may well fall into this category, but that is just a guess. There are a lot of other nutcase profiles that would fit this M.O.