A little-studied but very dangerous group of crimes is considered - multiple murders, when three or more people are killed. For Russia, with its high level of violence, this is a more than urgent problem that requires a scientific explanation and, on this basis, the adoption of the necessary preventive measures. The work is based on specific empirical materials, including selective statistical data, the study of criminal cases and the identity of criminals who committed multiple murders. A typology of such crimes is given, each type is carefully described, special attention is paid to the reasons for such dangerous criminal behavior, in connection with which phenomena such as sadism and necrophilia are studied. Factors contributing to multiple murders are analyzed. For scientists and practitioners, law enforcement officers, teachers, graduate students and students of law institutions of higher education.