I'll bet there are a few folks who are hoping, hoping HOPING that the shooter was a Muslim, so that they can say, "See? I knew it!"
They're probably going to be disappointed. There's also probably also a bunch of Arab-Americans (most being Muslims) who are hoping, hoping, hoping it was not a Muslim, as they do not want to see the hatred and bigotry further inflamed, which is the end goal of the formerly described group.