The spate of inquiries after homicides by mentally ill people in Britain since 1992 has stimulated concerns to improve management of the risk of violence. These reports repeatedly describe poor-quality care by professionals, citing a seeming disregard of personal distress and an unwillingness to permit access to support services. Despite the number of examples of such professional 'carelessness', there has been little attempt to understand them theoretically. This paper considers a theoretical framework which suggests that apparently insensitive behaviour stems from the deployment of rationalizations for denying care to mentally ill individuals, in situations in which professionals experience powerlessness to intervene effectively. Examples of such rationalizations are drawn from a study of 40 published inquiries after homicide. The authors conclude by considering the implications of their analysis for policy and professional development.