The standardized, indicated school-based prevention program "Networks Against School Shootings" (NETWASS) combines a threat assessment approach with a general model of prevention of emergency situations in schools through early intervention in student psychosocial crises and training teachers to recognize warning signs of targeted school violence. The present review summarized the underlying program theory, gives examples from German cases of severe targeted violence, gives an overview of the program components, and a summary of the evaluation study and its results. Finally, the NETWASS crisis prevention approach is reflected with regard to its feasibility for the prevention of violent extremism.