From the thesis Abstract: "Since the late 1990s, few incidents have captured the national spotlight more than active shooter events. These events are a significant concern to the public, and as questions arise surrounding these incidents, the focus often turns to law enforcement and its ability to protect the public. Often, law enforcement's response to inquiries surrounding prevention strategies concludes with officials explaining that they did everything possible to prevent the attack. This thesis analyzes the history of active shooter response and examines why law enforcement focuses more on response management than on prevention strategies. The project identifies issues when law enforcement, regardless of size or allocated resources, fails to establish a plan to track and monitor potential active shooter threats. Comparing four case studies--the Marjory Stoneman Douglas school shooting, Virginia Tech incident, Odessa-Midland attack, and the 1 October Las Vegas mass shooting--the research aims to identify investigative gaps that may have helped prevent the attacks. It categorizes the probability of preventing attacks based on available resources to law enforcement. The conclusion points to gaps with information sharing, planning, and resource allocation that could help agencies prepare for any future attacks."