Bullying, rejection, and social exclusion are often considered key contributing factors in school shootings, but recent studies have questioned their importance. One weakness in the previous research is its almost exclusive focus on U.S. American perpetrators. Therefore, we examined files of inquiry pertaining to seven school shootings in Germany that occurred between 1999 and 2006, with special attention to information on peer and teacher relationships. At the time of the offense, all perpetrators but one had a number of friends and acquaintances and were by no means socially isolated. Most, however, showed changes in their friendship patterns and had problems with some peers. In only three cases was there evidence of single bullying incidents. All perpetrators had problems with teachers prior to the offense. Our findings question that the results from previous research also apply to other samples. Problems with teachers represent an important risk factor which has been neglected in the research so far. Changes in friendship patterns may likewise constitute a warning sign. Our findings require consideration when developing prevention and intervention measures.