Active Shooter

Police Response to Mass Shootings

Written By:

Sgt. Kristofer Jenny

According to the Gun Violence Archive, there were 28 events categorized as mass murders and nearly 700 mass shootings  that occurred in the United States in 2021. Of those 28 mass murders, at least 12 of the incidents were perpetrated by “an individual actively engaged in killing or attempting to kill people in a populated…

According to the Gun Violence Archive, there were 28 events categorized as mass murders and nearly 700 mass shootings  that occurred in the United States in 2021. Of those 28 mass murders, at least 12 of the incidents were perpetrated by “an individual actively engaged in killing or attempting to kill people in a populated area,” or active shooter. In each incident, various law enforcement agencies responded to these events to render aid to the victims, contain the incident, neutralize, or apprehend the suspect and establish a crime scene for the related investigations that accompany these incidents. Each incident tests the preparedness of the public safety system in those affected communities. Despite the apparent prevalence of these events, it is important to remember that while each report of “shots fired” or a “shooting in progress,” has the potential to be an active shooter incident, simply arriving at a scene where shots are being fired does not warrant using “active shooter response” techniques.

The University of Texas at Austin shooting on August 1, 1966, is often recognized as a catalyst for the creation of Special Weapons and Tactics teams. During that event, the gunman killed 15 people and wounded 31 others while he shot from an elevated position for more than 90 minutes before he was stopped by responding police officers. The law enforcement response to mass shootings over the next couple of decades generally required officers to contain the incident and to call in SWAT. The intervention strategies and tactics used by law enforcement during “contained” mass shooting events continued to evolve after incidents like the San Ysidro McDonald’s shooting on July 18, 1984. During that incident, the suspect repeatedly shot patrons trapped inside the restaurant over a 77-minute period. The suspect killed 21 people and wounded 19 others before he was killed by a police sniper. SWAT teams refined their intervention tactics and continued to bear the primary responsibility for resolving these incidents until the Columbine school shooting in April 20, 1999.

The national interest in Columbine resulted in the term “active shooter” being applied to mass shooting events. The responding law enforcement agencies were heavily criticized for not intervening sooner. As a result, agencies across the nation began training officers in “rapid deployment” tactics. In essence, upon arriving at a mass shooting, the first four officers would form a contact team and move to the sound of gunfire to stop the killing of innocent people. Additional responding law enforcement resources would continue to form four-officer teams and move to the threat until the shooting was stopped and the scene was secured. As entities such as the Advanced Law Enforcement Rapid Response Training (ALERRT) Center in San Marcos, TX, continued to study active shooter events, specific tactics have been developed to enable a solo officer to isolate, distract and neutralize an active shooter.

While there continue to be incidents where quick-thinking, brave officers respond to and neutralize these perpetrators utilizing the latest tactics, there are a growing number of events where rapid response tactics are inappropriately applied to incidents that don’t involve an assailant who is actively attempting to kill innocent victims. Although these events don’t receive the same media attention, the results are no less tragic. Calls about “armed” or “barricaded” subjects, “shots fired” or “active shooter” even though no shots have been fired, have all resulted in avoidable tragedy. This can be a result of inappropriate priming. This can be caused by our training, an inappropriate analysis of critical incident videos or because of erroneous information relayed by dispatch.

When responding to a mass shooting/active shooter event, the law enforcement mission should be to stop the killing and stop the dying. Law enforcement officers must consider the information provided by public safety dispatchers and combine that with their individual observations including the sights, sounds and smells when they arrive on scene, to dictate the tactics they will use. The active shooter events in Boulder, CO, in March 2021 and San Jose, CA, in May 2021 illustrate this point. In both incidents, officers responded to reports of shots fired, and in one of the events, it was reported as an active shooter prior to the first officer arriving on scene. In both incidents, the LE resources began to establish containment while observing the scene – the focus being incident or scene containment. Once the “stimulus” was perceived (shots heard by officers on scene), this observation was shared with other officers, and they immediately changed tactics and began moving to the sound of gunfire. During the LE response to the Parkland shooting at Stoneman Douglas High School in February 2018, once LE resources entered the school buildings and they did not encounter a gunman, they immediately established security and began to treat the wounded. Absent the stimulus of shots fired, they transitioned to the “stop the dying” phase of the event in that building, while other resources continued to search the campus. Ensuring officers have a clear understanding of “stop the killing” and “stop the dying” mission, will allow them to maintain initiative and act implicitly to save lives.

An analysis of the FBI’s 20-year review of active shooter incidents reveals the following:

  • The state of California has experienced more active shooter events than any other state over the past 20 years
  • Most active shooter incidents occur in businesses open to the public, followed by schools and other open public spaces
  • The suspect is killed by police or commits suicide in just over half of the incidents, otherwise the suspect is usually apprehended away from the scene
  • The suspect is armed with a handgun in 67% of the incidents and a long gun in approximately one-quarter of the incidents

Our communities expect law enforcement to resolve these incidents efficiently and professionally. We have an obligation to continue to learn from the past and prepare for future events. The time to prepare comes before the time to perform.



Kristofer Jenny is a Sergeant with the Napa Police Department and is currently assigned as the Administrative Sergeant, which oversees training and special events planning as well as the department’s Body Worn Camera program. During his 21-year career in law enforcement, Kristofer has worked in Patrol, Motors and Administration. He has served in ancillary assignments including computer crimes investigator, recruit training officer, less lethal instructor, traffic reconstruction, rangemaster and SWAT.