What is Upstanders

This chapter considers ways to detect mass shootings before they occur. It focuses on the role of leakage in prevention, whereby the communication of an intention to do harm can be used to assess the nature and viability of a mass shooting occurring. Eleven case studies of mass shootings are used to assess leakage and other warning signs displayed prior to these attacks. Documented are possible types of leakages, audiences for leakages, ways leakages were communicated, and other types of warning behaviors. Findings from interviews with threat assessment experts are also discussed in relation to the role leakage plays. It is hoped this chapter will go some way to informing risk and threat assessment procedures, which will be discussed in more detail in the subsequent chapters.