Mass Murder and Consecutive Suicide in Switzerland: A Comparative Analysis

Abstract

Mass murder, the killing of three people in a timely and locally narrowly defined space, is a rare event with extensive consequences on society. In many cases, mass murders end with the offender’s suicide. We identified 49 cases of mass murder in Switzerland that had occurred between the years 1972 and 2015. We were granted access to official files of 33 cases. The aim of our study was to identify distinct risk factors for mass murderers who had committed suicide after the crime (MMS) and those who had not (MM) by analyzing differences in sociodemographic, psychological, and criminological features. We identified 16 MMS and 17 MM. The majority of MMS was familicides. Their motive was mainly a perverted sense of loyalty, as opposed to that of MM revenge. The aggression of MMS would mostly be instrumental, the one of MM also reactive. Threats were highly prevalent in both groups, with a higher rate of specific threats in MMS and more generalized threats in MM. They did not differ in the prevalence of mental disorders or rate of prior suicidal ideation. Both type of offenders mainly used firearms. Military weapons were of no importance, contrary to their role with suicide in Switzerland. Mass murder in Switzerland is an extremely rare event that makes the drawing of general conclusions somewhat difficult and the establishing of new laws futile. Our conclusion that the aggression of MMS is premeditated, however, could be helpful with the assessment of future putative offenders.