I'm not sure if it's a terrorist attack, which would be the automatic assumption. It just doesn't seem profesional enough. I mean, the 9/11 attack, the Spanish attack, the Phillipines attack, and the numerous attacks on Israel, all caused numerous casualties and deaths. All of the attacks outside of Israel have caused triple-digit casualties (at least all that I've read). A simple shrapnel bomb, without a single fatality, in a rather quiet neighborhood just seems more along the lines of some Columbine thing. I just think that profesional terrorists would do something more destructive. This seems like the work of ametuers.
Of course, it could be some bored German youth. On the other hand, given the role of global Islamic dogma, it's also possible that a local cell, without any conection to international terrorists, decided to strke their own blow against "the Great Satan". Germany and France both have disgruntled Muslim populations and one of the major concerns about bin Laden was that he would inspire other groups to acts of terrorism. That's my guess: a group of disgruntled German Muslims were inspired by bin Laden and other terrorist groups, possibly over the escalating situation in Iraq, and built their own bomb from instructions of the Internet.
