Explain the concept of active shooter incidents and their historical background.

The concept of active shooter incidents refers to situations in which an individual or a group of individuals engage in armed violence, typically using firearms, in a populated area. These incidents are characterized by the active and indiscriminate nature of the attack, as the perpetrators target random victims with the intent to cause harm, injury, or death. Active shooter incidents are often unpredictable and can occur in various settings, such as schools, workplaces, public venues, or community spaces. Historical Background: The term "active shooter" gained prominence in the late 1990s and early 2000s in response to a series of high-profile mass shooting events in the United States. Notable incidents that influenced the concept's development include the Columbine High School massacre in 1999, in which two students killed 12 students and a teacher before committing suicide, ....