Interesting to me is that, further down the page, they mention that he's of Albanian origin. Whether this had anything to do with it or not, I do not know, but... it occurs to me that Albania is primarily a Muslim country. (I've got friends from church who are planning to go there as missionaries)
It´s not the gunman who is of Albanian origin, but one of his victims. The name of the gunman is Tim Kretschmer, that´s actually very much a German name.
And the newspaper is definitely not the best source you can get. It´s pure tabloid, and contains, according to a German band mainly "fear, hate, tits and the weather report".