The killing of another human being is an execrable act and universally condemned. Simpler societies have informal ways of seeking retribution (Bohannan 1960; Hoebel 1954). Ancient states and civilizations evolved formal procedures and complex institutions for evaluating culpability, apportioning blame, and authorizing appropriate sanctions (Ng 1990; Robinson 1996). The evolution of the insanity defense in Anglo-American society has culminated in assigning to psychiatry and psychology the important task of determining whether the mental state of a person who perpetuates homicide meets criteria for legal sanction. Differences involving the traditional model of reasoning about human action that is standard in psychiatry compared to law have been discussed. A common basis of understanding and procedure for assessing responsibility has evolved (Moore 1984). However, usually neglected is the influence that culture has in shaping behavior of homicide and its forensic psychiatric assessment. Two cases are presented to examine why and how culture is influential in matters of homicide.