By Jillian Peterson

This is the Final Report on the goals and achievements of a project that created a database on patterns in the lives of mass shooters to assist in informing policymakers and practitioners in developing and implementing prevention and intervention strategies for mass shootings. Informed by existing datasets, the research literature, and frequently asked questions about mass shooters, this project compiled a list of variables to be coded and developed a codebook. The codebook was piloted on a small random sample of test cases and refined. Open-source lists of mass shootings were developed from major news outlets. Among the variable categories are leakage of the killers’ plans, crisis signs, victim characteristics, firearms possession and use, role of psychosis in the shooting, behaviors related to violence, mental health, family characteristics, and social and interest groups. The report also contains findings from the database on mass shooting trends; shooter demographics; trauma, suicidality, and crisis; mental health; and warning signs

St. Paul, MN: Hamline University, 2021. 38p.