What best describes an "active shooter"?

An active shooter is defined as an individual who is actively engaged in killing or attempting to kill in a populated area. This situation typically involves the use of a firearm in a manner that poses an immediate threat to public safety, as the individual targets multiple victims in a location where many people are present.

This definition is critical for law enforcement and emergency responders to understand because it dictates the urgency and specifics of the response required in such incidents. The focus is on the immediate risk to life and the necessity to neutralize the threat as quickly as possible to protect lives.

While other scenarios listed may involve dangerous behavior or unlawful possession of a weapon, they do not convey the same immediate lethal threat that categorizes an active shooter situation, which is fundamentally about ongoing violence targeting civilians.