May 04, 2023
The 5 Stages of Mass Shootings and What You Can Do To Prevent One At Your Organization
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With the surge of mass shootings that plague our nation, organizational leaders are prioritizing how to prevent mass shootings—and the answer isn’t simple. 

Adding more security personnel or installing metal detectors won’t solve the problem. We’ve seen this time and time again in mass shooting tragedies. If anyone approaches you with a “cure-all” solution, you should be wary.

Gun-related violence is a complex matter that requires multiple layers of security, technology, protocols, and more. So, where do you even start? In this article, we break down the following five common stages of mass shootings and what you can do to strengthen security at every stage.

Stage 1: Warning Signs

Stage 2: Shooter’s Preparation 

Stage 3: Active Shooting

Stage 4: Response & Threat Containment

Stage 5: Reunification

Improve Your Security By Learning the 5 Stages of Shootings

Each stage of a mass shooting or active shooter incident has its own set of risks and vulnerabilities, therefore requiring different types of solutions.

Some of the most common solutions that leaders look to for active shooter prevention include metal detectors, door locks, or barricades. These measures can be helpful, but it’s critical to understand that they do not address all five stages of a mass shooting. In fact, most security measures, like the examples aforementioned, only address the Active Stage of a mass shooting—and in some cases, could even potentially put the people they are trying to protect at greater risk.

Typical Reactive Plan


Swipe or click to turn this reactive plan into a proactive plan.

Balanced Proactive Plan


Proactive visual gun detection enhances multiple layers of existing security by providing early alerts and situational awareness.

If an organization lumps all of its security budget into a single type of resource that addresses only one out of five stages, it is not prepared to protect its people. 

Below, we explain each stage with real-life examples and provide recommendations for what types of solutions are needed.


People don’t just randomly wake up one day deciding that they will commit a mass shooting. In the majority of cases, there’s some build-up—a series of events that plant a dark seed in someone’s mind. 

More than 80% of mass shooters had marked changes in behavior that were noticeable to others before they carried out their crimes. 

Voice of America

Example #1: Robb Elementary School Shooting in Uvalde, Texas

The Texas House Committee released a detailed 77-page report that chronicles the trail of warning signs displayed by the gunman ahead of the tragic Robb Elementary school shooting. 

In fact, there were so many warning signs, that the gunman’s peers actually began calling him “school shooter.” Below are some of the public warning signs that should have been cause for intervention:

  • Days before the attack, the gunman wrote an ominous post on social media that he had plans to do something that would “put him all over the news.”
  • On social media, he shared disturbing content like online videos of beheadings and violent sex.
  • On social media, the gunman shared footage of himself driving around, holding a plastic bag containing a dead cat, and pointing BB guns at people.
  • The gunman went from being described as a “wonderful student” with a “positive attitude” in grade school into an at-risk student with failing grades and more than 100 school absences a year.

Example #2: Kroger Shooting in Collierville, Tennessee

On September 23, 2021, an ex-Kroger employee in Collierville, Tennessee went on a rampage shortly after being fired. 

This shooting resulted in 15 injuries and 1 death, and the company was later sued for $10M because it was claimed that they should have known that the shooter presented a danger after being fired based on negative behavioral history.

In the court filing, the lawsuit read:

“”…Thang had a history of anti-social, antagonistic, volatile, unstable, threatening and predictably dangerous behavior at all times pertinent hereto. Thang had a history of confrontations and disagreements with other individuals including employees and agents of Kroger and its invitees.”

Court documents also note that the gunman, Thang, was noticeably angry after being fired and despite his poor behavioral history, the company allowed him to return to the store without an escort. 

“This guy, he showed signs something wasn’t right,” a co-worker said. “We should never turn a blind eye to something like that.”

Potential Solutions

With so much leaking happening over social media before an attack, social media monitoring companies have formed in an attempt to identify risks early on. However, there are many concerns about this type of technology infringing on students’ and workers’ privacy rights. 

Something else to consider is that there is currently little proof to back up the efficacy of social media monitoring. In fact, Uvalde Consolidated Independent School District contracted with a social media monitoring company but was still unable to prevent the Robb Elementary school shooting. 

Instead, organizations should focus on developing and actively maintaining a Crisis Intervention Program. School shootings typically don’t happen at random. Additionally, creating an environment where people feel safe about voicing their concerns without the fear of being punished is critical.

Recently, a Texas student was suspended for expressing their concerns about an ominous comment, and it’s cases like this that discourage people from speaking up. Many organizations support a “See Something, Say Something” policy—but how are people supposed to say something if they fear backlash?


  • More than 80% of mass shooters had marked changes in behavior that were noticeable to others before they carried out their crimes, and 72% were suicidal either before or at the time of the shooting.
  • The best thing organizations can do is cultivate and maintain an environment where people feel safe expressing their concerns. If everyone were to report the behavioral warning signs they witnessed, more can be done for threat assessment and prevention.


    The Shooter’s Preparation stage occurs right before the shooting, as the shooter mentally prepares for what they’re going to do. Compared to the other stages of a mass shooting, this stage is on the shorter side—but it’s not as short as most would assume. 

    Many people believe that mass shooters arrive on the scene guns blazing, but this isn’t true in the majority of cases. Instead, mass shooters will mentally prepare or “stage” what they are about to do in parking lots, stairwells, or outside of buildings. 

    Essentially, it’s common for an active shooter to visualize what they’re about to do for several minutes before the attack.

    In many cases, shooters can be seen “preparing” on security camera footage before an attack. The sad truth is that most security cameras are used for forensics evidence gathering and not used to prevent a tragedy from happening. 

    But if there is a way to detect illegally brandished guns and alert authorities during this Preparation stage, the outcome could have been significantly different. 

    Example #1: Walmart Mass Shooting in El Paso, Texas

    On August 3, 2019, a man entered a Walmart in El Paso, Texas with a firearm. He entered the store at 10:15 AM and opened fire, in what he now admits was a targeted hate crime. A 911 call was made at 10:39 AM, and first responders arrived at the scene six minutes later at 10:45 AM.

    Before the gunman was located and arrested, he killed 23 people—including a grandfather who acted as a shield protecting his wife and granddaughter—and injured 22 others.

    Walmart Shooting Timeline (1)

    Victims were stuck inside the store for approximately 30 minutes before first responders arrived. Would the outcome have been different if the police had been notified as soon as the shooting began? Or, better yet, before the shooting began?

    The gunman in this mass shooting was caught on camera with his firearm in the parking lot at 10:08 AM, seven minutes before the shooting began. But, like in most cases, organizations do not have the resources to assign security personnel to watch all camera feeds at all times. 

    Example #2: Sandy Hook Elementary School Shooting in Newton, Connecticut

    On December 14, 2012, a 20-year-old man drove to Sandy Hook Elementary School, a school he attended as a child. He parked his car and at approximately 9:30 AM, walked to the front entrance of the school, openly carrying a rifle, along with two pistols and a supply of ammunition. 

    After realizing the doors were locked, he shot through the glass windows of the entrance doors to make his way to the front lobby. It wasn’t until 9:35 AM that a 911 call was made. At this point, four adults were already shot, two of which were fatal. The first officer arrived three minutes after the 911 call, and a small team of police entered the school eleven minutes after the first call at 9:44 AM.

    Critical minutes—seconds, even—matter in active shooter cases. Relying on 911 calls to be made is not good enough, as any delay in response could mean lives lost. 

    What if police had received an alert at 9:30 AM when the shooter was openly carrying a firearm across the school parking lot? Law enforcement could have been at the scene minutes after, and possibly before the shooter caused any harm.

    Potential Solutions

    Many people assume adding more on-site security is the answer to this problem, but the reality is that no matter how many security personnel are on staff, it’s impossible for them to monitor all cameras for all threats at all times.

    Even if you have a large team of security personnel actively patrolling, they will still struggle to respond quickly if they hear gunshots but don’t know exactly where the shooter is or what they look like. 

    Proactive visual gun detection technology installed on existing digital security cameras can send human-verified gun detection alerts as soon as guns become visible on camera and provide security personnel with critical situational awareness. 

    In both examples above, first responders would have received a verified gun detection alert, accompanied with the shooter’s exact geolocation and photograph, as they were preparing in the parking lot. 


    • In many active shooter cases, the shooter visibly brandishes a gun on camera before acting—sometimes for several minutes or even up to 30 minutes.


    • On-site security is a critical part of any organization’s security plan, but it’s impossible for them to have eyes on all potential threats 24/7.


    • Early detection and situational awareness are the best means of security during the Preparation stage because they drastically improve response time, which can in some cases stop the shooting from happening altogether.


    The Active Shooting stage of a mass shooting begins once the first shot is fired. As anyone can imagine, this is when panic and chaos ensue. People run away from the shooter. Some try to look for a safe place to hide away from the shooter’s trajectory.

    There’s one thing on everyone’s mind at this point: survival. This means people aren’t reaching for their phones to call 911 right away—especially if they’re trying to hide and make themselves unseen and unheard by the shooter. 

    If a bystander can report the incident, they won’t have the correct information about the shooter’s whereabouts or identity—and providing the wrong information can be even worse than no information. 

    To sum it up, there is zero clarity during the Active Shooting stage of a shooting. Without up-to-date, accurate details like the shooter’s identity and whereabouts, locating and stopping the threat is a near-impossible task for law enforcement to perform quickly and safely. 

    Below are just a couple of examples of how lack of clarity has a direct impact on active shooter response:

    Example #1: Henry Pratt Company Shooting in Aurora, Illinois

    On February 15, 2019, a man who was fired from his job at a manufacturing company went on a rampage that left five workers dead and five officers injured. 

    That morning of the shooting, the shooter said to a co-worker, “If I get fired, I’m going to kill every mother f***** in here. I am going to blow police up.”

    According to reports, the employee knew that the shooter often had a gun in his car but did not believe he was serious. It’s also believed that the shooter brought the gun and ammunition inside the building when we arrived at work that day.

    Calls about the shooting began at 1:24 PM and police officers arrived four minutes later. Despite the fast response to the scene, it took an hour and a half for the police to scour the 29,000-square-foot warehouse, locate the shooter, and stop the threat.



    Surveillance footage was released of the shooter pacing back and forth in the company’s lobby with his gun. He paces for about a minute, shoots out the lobby doors into the parking lot, and props open a door.

    If the officers had this type of real-time situational awareness, they may have been able to contain the threat faster while reducing risks to the responding officers.

    Example #2: Marjory Stoneman Douglas School Shooting in Parkland, Florida

    One of the deadliest mass shootings in the United States happened at Marjory Stoneman Douglas High School on February 14, 2018.

    The shooter arrived at the school at 2:19 PM. Surveillance footage shows him walking through the stairwell, visibly brandishing his firearm at 2:21 PM. Approximately 15 seconds later, he begins firing into classrooms. At 2:22 PM, the school’s fire alarms go off, prompting students to evacuate.

    At 2:23 PM, the school resource officer issues an alert and says, “Be advised we have possible — could be firecrackers. I think we have shots fired, possible shots fired, 1200 building.”



    In this video compilation of videos, radio calls, and visual timeline, you can clearly see and hear the chaos and confusion. Students call 911, pleading for help, as the school resource officer and first responders search the 12-building campus—nowhere near the shooter’s actual location.

    Had school administration and first responders received an alert as soon as the shooter was caught with a gun on camera, there would have been no mistaking the gunshots for firecrackers—or as some students thought, an active shooter drill. And had officers had the shooter’s geolocation, which was captured on surveillance footage, they would have known which building to enter and could have contained the threat faster, saving lives.

    Potential Solutions

    Many organizations will invest in barricades or automated door locks to help protect their people during an active shooter event.

    But without situational awareness, choosing to lock yourself into a room may not be the best course of action. For example, what if the shooter decides to start a fire? In that case, locking or barricading yourself is not the best course of action, and these security tools are now turned against you.

    Ballistic whiteboards are another security tool schools are investing in, which are intended to shield students and teachers from the shooter. However, if an active shooter gets hold of a ballistic whiteboard, they can easily use that as a shield against law enforcement. 

    Situational awareness is the only thing that can never be turned against you. It will always better inform law enforcement and security personnel so they can act quickly with the best course of action.


    • The glaring issue during the Active stage of a mass shooting is a complete lack of situational awareness.
    • Details like the shooter’s photograph and location are critical to stopping the shooter faster.
    • Organizations need a source of truth with real-time updates to provide law enforcement, instead of leaving the burden of providing situational awareness to the innocent bystanders and victims making 911 calls.

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    The Response stage involves how first responders assess the scene to:

    • Understand the threat
    • Locate and stop the threat
    • Provide medical triage for victims
    • Help innocent people get away from the danger and to a safe location.

    During this stage, providing security personnel and first responders with situational awareness is key for improved response. 

    This is because there are different protocols for how local law enforcement responds. For example, if they believe it is a hostage situation, instead of a suicide mission or mass shooting event, the police are not going to go into the building to confront and stop the threat. Instead, they are going to secure the surrounding area, and wait it out. 

    Assuming the wrong protocols can cost lives. Below are a few examples:

    Example #1: Pulse Nightclub Shooting in Orlando, Florida

    The Pulse Nightclub shooting is one of the deadliest mass shootings in U.S. history, with 49 people killed and 53 wounded. The shooting began at 1:58 AM, and it wasn’t until 5:53 AM that the shooter was confirmed dead.

    A study concluded that 16 of the victims might have lived if they had received basic EMS care within 10 minutes and made it to the hospital within an hour, which is the national standard.

    Officials say that it was impossible to know if there were one or multiple shooters at Pulse which prevented first responders from providing care for victims in time. While some incapacitated victims were carried out of the nightclub by officers, other victims grabbed officers’ ankles as they walked by, waiting to be saved. 

    The Fire Department was brought in to help, as they had bulletproof vests that could each hold enough supplies to treat 10 to 15 patients. However, with the policy for this new equipment incomplete, the Fire Department told paramedics to stay three blocks away if they felt uncomfortable with the scene. Officers, firefighters, and paramedics were unsure what they were up against, and the mass shooting was treated as a hostage situation that carried on for hours as victims bled out. 

    Had responding officers had real-time critical situational awareness, they would have known that there was only one shooter present, which could have drastically changed their response assessment. 

    They may have also been able to respond faster if they had received the alert as soon as the shooter walked in with a visibly brandished gun, as released surveillance footage shows. 

    Example #2: Robb Elementary School Shooting in Uvalde, Texas

    Pulse Nightclub shooting survivor, Brandon Wolf, says that the missteps in the Uvalde shooting response echo that of the Pulse massacre.

    “A total failure of police response in Uvalde cost children their lives,” Wolf said. “We know a similar horror. While police waited three hours to breach Pulse Nightclub, 13 of our friends and family members died on the bathroom floor.”

    Similarly to the Pulse Nightclub shooting, the Robb Elementary School Shooting was treated as a hostage situation with 376 police officers on the scene.

    A report by the Texas House Committee says:

    “Despite the immediate presence of local law enforcement leaders, there was an unacceptably long period of time before officers breached the classroom, neutralized the attacker, and began rescue efforts. Given the information known about victims who survived through the time of the breach and who later died on the way to the hospital, it is plausible that some victims could have survived if they had not had to wait 73 additional minutes for rescue.”

    Example #3: Marjory Stoneman Douglas School Shooting in Parkland, Florida

    Video delays misled first responders at the Marjory Stoneman Douglas School shooting—a mistake that cost lives. 

    Nearly half an hour after the shooter fled the school, police thought they were still seeing him live on security footage, which slowed down efforts to rescue injured students in that building who were bleeding out.

    A criminal justice professor weighed in and said, “That’s going to slow you down because you think that’s good information, but it’s not good information.”

    When responding to an active shooter event, there are two primary goals: stop the killing and stop the bleeding. Accurate, real-time situational awareness could have helped first responders stop the bleeding faster and potentially save lives.

    Potential Solutions

    Chaos, lack of clarity, and inaccurate data all directly impact active shooter response. 

    Most organizations believe that the more on-site security, the better the response. But the examples above all go to show that it does not matter how many officers respond if they are still struggling with a lack of situational awareness.

    Real-time situational awareness is the only way we can address the core challenges that security personnel and first responders face.


    • Situational awareness directly impacts how first responders assess an incident and respond.


    • Real-time situational awareness helps first responders make better, faster, and more effective decisions to stop the killing and stop the dying.


    Should a school shooting occur, how do parents know where to unite with their children? Or in public and workplace shootings, how do the victims safely reunite with their loved ones?

    This stage of a shooting is known as the Reunification stage. Reunification is the process of bringing together displaced victims with their families, and the goal of any organization is to help families achieve timely reunification.

    Example #1: Oxford High School Shooting in Oxford, Michigan

    After the Oxford High School shooting, a nearby Meijer grocery store temporarily shut down operations to serve as a reunification center. 

    After the shooting, the school was placed on lockdown with some students sheltering in locked classrooms as officers searched the premises. Once buildings were cleared, these students were brought to the Meijer grocery store across the street.

    Example #2: Half Moon Bay Shooting in Monterey Park, California

    After the Half Moon Bay shooting, a reunification center was set up a few miles from the scene. Approximately 40 adults and 13 children waited at the center to be reunited with loved ones they still hadn’t heard from. 

    People in the community knew that seven people were killed and one critically wounded, but until the victims are identified, many people in the community anxiously waited and feared the worst.

    Potential Solutions

    Reunification exercises can be difficult to practice because they require significant planning and resources. At the very least, organizations need to invest time in developing a solid reunification plan that includes a written operational guide, a pre-identified reunification facility, and communication protocols. 

    Reunification software can help you facilitate the process, and mass notification systems can help keep people informed and connected during reunification. These tools can help make the reunification process more efficient.


    • Depending on the incident, reunification can take anywhere from hours to days, and ineffective reunification can have a traumatic impact on anyone involved and the community at large.
    • Reunification protocol should be reviewed and/or practiced during active shooter training.

    What You Can Do To Prevent and Mitigate A Shooting

    First and foremost, be wary of security vendors who claim to do it all. There is no “cure-all” solution to stop mass shootings from happening. There are, however, expert-recommended guidelines you should follow to create a strong, multi-layered security system that reduces the threat and impact of shootings.

    Step #1: Assess your current security strategy. What tools and protocols do you currently have in place to prevent gun-related violence? Are these solutions reactive (ie only work after a shooting has begun) or do you also have proactive solutions in place?

    Step #2: Address each stage of a mass shooting. Is your organization doing everything possible to address all five stages of a mass shooting, or are you lumping all of your resources into solutions that only address one or two stages? 

    Step #3: Make situational awareness a priority in your security strategy. A recurring theme in this mass shooting breakdown was the lack of situational awareness that organizations and law enforcement struggle with. In every single active shooter situation, people would have benefited from accurate, real-time situational awareness. 

    Proactive Visual Gun Detection Can Be An End-to-End Solution

    Proactive Visual Gun Detection provides you with more than gun detection alerts—it provides your organization with advanced situational awareness that improves response and also enhances many other layers of security. 

    When you have better situational awareness, your on-site security can act faster. When you know exactly where the threat is, you can provide better direction than “Run, Hide, Fight,” which is an outdated protocol that can be more harmful than helpful. 

    By addressing the vulnerabilities and risks present in stages two through five of a mass shooting, ZeroEyes’ proactive visual gun detection is one of the most comprehensive solutions to reduce the threat and impact of mass shootings.

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    Rob Huberty
    Rob Huberty is the Chief Operating Officer & Co-Founder of ZeroEyes. Before founding ZeroEyes in 2018, Mr. Huberty worked as a Pathways Operations Manager at Amazon, leading cross-functional teams, initiating process improvement, developing standard operating procedures, and serving as a mentor for his teammates. He served in the U.S. Navy as a Navy SEAL where he collaborated with international governments to conduct special operations, trained foreign forces to ensure mission success, and employed innovative problem solving.

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