Background Familicide is defined as the killing of a whole family and, numerically, a form of “mass murder” (more‐or‐less three simultaneous killings). Switzerland has a lower rate of homicide than most other countries but a comparatively high share of homicides within the family. Aim The aim of this study is to describe a complete national sample of familicides and compare them with other types of mass murders in the country over the same period. Methods All cases of three or more unlawful homicides in one event in Switzerland between 1972 and 2015 were identified from court records and socio‐demographic, criminological, and psychological variables were extracted. Given small numbers, we rely on narrative comparisons. Results There were 20 familicides in the 43‐year study, with 82 victims between them as well as six felony‐associated mass murders accounting for 19 victims and nine public mass murders with 44 victims. Only one familicide was a woman; mean age was 39.5 years (range 19–57 years). Most were in employment. Only four had a prior psychiatric history. Nine had a history of violent or intrusive behaviour, but a prior criminal conviction was rare. In all but one case there was evidence of psychosocial stressors; eight men were facing separation from a spouse. Just over half used guns, but only three used army weapons. The main difference between the familicides and the other mass killers was the much higher rate of suicide among the familicides. Conclusions Familicides in Switzerland appear to be rare suicidal acts, generally carried out by previously successful and apparently stable middle‐aged men with often an inconspicuous psychiatric history or criminal record, differing considerably from other groups of mass killers. Expert responses, like the recently established multidisciplinary “threat management boards” in Switzerland, should bear in mind that the likely competent men involved may be good at covering their intent even from themselves.

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. Public Significance StatementMass murder is a rare act that, by its extreme violence, stokes the emotions of the public and hence implies an extraordinary challenge for risk assessment professionals. Mass murder is closely linked to suicide. In this article, we report about the particularities of mass murder with consecutive suicide in Switzerland, a country with a generally low incidence of violent criminality. Mass murders with consecutive suicides in Switzerland are premeditated acts executed by rather well-off middle-aged men suffering from a long-lasting strain and/or personality disorder who never sought professional help and who mainly killed their family and then themselves.