You have a point. We don't have any good information, and it may be some time before we do. Although, this is a rather strange case, at least at first glance. Every other terrorist who has either attempted or committed an act of aggression against the US since 2002 has not only been identified as Muslim, but they've all been said to have "radicalized over time." All of them were known to someone (possibly several someones) to have been showing signs of Islamist behavior. We've had two of these guys' uncles speak out, along with their father, apparently (Saw that on a Yahoo News story) and none of them have said "They've been getting more radical over the years" (cf Umar Abdulmutallab).