History of Active shooter in Timeline

By Popular Timelines Editorial Team · Updated: October 1, 2025

An active shooter is someone engaged in an ongoing mass shooting, typically targeting victims indiscriminately and on a large scale. These individuals often intend to be killed by law enforcement or commit suicide. The broader term 'active killer' may also refer to perpetrators of mass murder in general.

2000: FBI begins tracking active shooter incidents

In 2000, the FBI began tracking active shooter incidents as part of a study that would later be published in 2014.

2006: Average annual active shooter incidents tracked by the FBI

From 2000 through 2006, the FBI tracked an average of 6.4 active shooter incidents per year.

2007: Increase in active shooter incidents

From 2007 through 2013, there was an increase in active shooter incidents, averaging 16.4 incidents per year, with 366 of the 486 deaths occurring during this period.

2008: Beijing Drum Tower Stabbings

In 2008, the Beijing Drum Tower stabbings in China resulted in 1 adult death, one of several mass casualty events critiqued as beyond the terminology of 'active shooter'.

2008: DHS Definition of Active Shooter

In 2008, the United States Department of Homeland Security (DHS) defined an active shooter as an individual actively engaged in killing or attempting to kill people in a confined and populated area, where firearms are predominantly used, and victim selection appears random.

2011: 2011 Tucson shooting

In 2011, Bill Badger in Arizona, and others, showed the success of civilians attacking the attacker in a range of incidents, according to statistical analysis and tactical recommendations.

2012: Investigative Assistance for Violent Crimes Act of 2012

In 2012, following the Sandy Hook Elementary School shooting, the Investigative Assistance for Violent Crimes Act of 2012 was passed in the United States. This act clarified the statutory authority for federal law enforcement agencies to provide investigatory assistance to the States.

2013: FBI study period ends

In 2013, the FBI's study period ended, after which, in 2014, the FBI released a report covering active shooter incidents from 2000 through 2013, identifying 160 incidents and 486 deaths.

September 2014: First FBI report on active shooter incidents published

In September 2014, the FBI published its first report on active shooter incidents, initiating a program to research such incidents and develop training resources for law enforcement agencies, excluding gang- and drug-related incidents.

2014: Calgary Stabbing

In 2014, a mass stabbing occurred in Calgary, Canada, resulting in the deaths of 5 adults, highlighting the issue of mass casualty attacks beyond just firearm incidents.

2014: FBI report on active shooter incidents covered the period 2000 through 2013

In 2014, the FBI released a report covering active shooter incidents from 2000 through 2013, identifying 160 incidents and 486 deaths.

2018: Active shooter incidents in 2018

In 2018, there were 30 active shooter incidents in the U.S., according to the 2022 FBI report.

2019: Active shooter incidents in 2019

In 2019, there were 30 active shooter incidents in the U.S., according to the 2022 FBI report.

2020: Active shooter incidents in 2020

In 2020, there were 40 active shooter incidents in the U.S., according to the 2022 FBI report.

2021: Increase in active shooter incidents

In 2021, there were 61 active shooter incidents in the U.S., resulting in 103 deaths and 140 injuries. Most active shooters were male, and incidents increasingly involved multiple locations.

2022: FBI report indicates rise in active shooter incidents in 2021

According to the 2022 FBI report, active shooter incidents rose in 2021 to 61 incidents, with 103 victims killed and 140 wounded, up from 40 in 2020 and 30 in each of 2018 and 2019.

2022: Casualties in active shooter incidents rise

In 2022, there were 50 active shooter incidents, with 100 people killed and 213 injured (not including the perpetrators), according to the 2023 FBI report.

2023: FBI report indicates casualties rose in 2022

According to the 2023 FBI report, the number of casualties in active shooter incidents rose in 2022, with 100 killed and 213 injured (not including the perpetrators) in 50 incidents.