From the thesis Abstract: "With the rising threat of active shooters, armed off-duty and retired law enforcement officers may prove to be an effective tool in American homeland security. Yet, while the number of active shooter and critical incidents in the United States have continued to rise, the number of non-traditional response interventions has remained minimal. Unfortunately, the presence of armed, off-duty law enforcement officers can create other problems, often referred to as blue-on-blue encounters. This thesis examines the questions: Can tools such as Hero911 mitigate some of the major risks associated with self-dispatch? How can off-duty or plainclothes officers be best incorporated into active shooter response? Finally, what processes can make utilization of non-traditional responders safer for all? This thesis concludes that over the past 20 years of active shooter responses, first responders have missed an opportunity with respect to the use of non-traditional responders. On- or off-duty non-traditional responders serve as a force multiplier, which widens the pool of available responders. Use of any technology is not without risks, and to avoid more confusion during an active shooter event, training is paramount. Properly used, tools such as Hero911 can reduce the risks involved in non-traditional officer response."