This article highlights the fact that although we may have profound faith in the goodness of human nature, we never know when a killer is walking among us. The recent spate of mass shootings at schools and other locations underline the presence of disturbed people in our midst. Besides defending ourselves, we need to ask ourselves what in our society is provoking this disturbing behavior. Certainly the ubiquity and ease of acquiring guns is one cause, but there may be others that need attention as well.