By The U.S. Federal Bureau of Investigation

In 2014, the FBI published its first report, A Study of Active Shooter Incidents Between 2000-2013, and subsequently published annual and bi-annual reports reflecting its continued research into active shooter incidents based on the FBI’s definition of an active shooter. Through its initial research, the FBI identified and reported on 305 active shooter incidents occurring in the United States between 2000-2019. It was later determined there were potentially other active shooter incidents fitting the FBI’s active shooter definition that had not previously been identified. …. As a result, the FBI evaluated and identified an additional 28 active shooter incidents that occurred between 2000 and 2019, bringing the total designated active shooter incidents during this time period to 333. … This valuable information is intended to assist law enforcement and the public in developing strategies to stop active shooter threats, prevent acts of violence, and prepare for, respond to, and recover from such incidents.

Washington, DC: FBI, 2021. 35p.