It is sad, but the police are so far saying they don't think it was politically motivated. Remember, Swedish politicians seem to attract an awful lot of unwanted attention. Back in 86, one PM was killed with his wife, and a few years later some animal rights person shot another politician.
BTW, please feel free to log my response to this. It is my perception that the eurocrowd is quite a bit worse in their responses to sad events in the US, so all I ask is that you not limit the scope of your attention to americans. What you see in the mirror may sadden you.