By August of 2007, Ackermann, then 19, had left his native Cologne, Germany, for Vienna, Austria, where he was staying in short-term housing for the mentally ill and homeless run by a private charity. He shared a room with Josef Schweiger, 49, who had been in the facility since that June. Weekly social workers don't seem to have been alarmed by Ackermann's behavior or concerned about the pair's feuds. But neighbors on the family-filled tenement block who argued with the increasingly disturbed Ackermann, saw him crawling naked through the yard howling at the moon, or dumping what appeared to be blood from his window, realized the teen was dangerous.