Mass shooters killed 31 people last weekend in El Paso, Texas, and Dayton, Ohio, and three people in Gilroy, California, last month, including two children. The week was the deadliest for mass shootings and fatalities this year, whichever way one chooses to count them.

In the wake of these incidents, we often hear “no one could have seen this coming,” or “this person just snapped.” But what do we know about the perpetrators of mass shootings?

Recent reports from the U.S. Secret Service National Threat Assessment Center and the FBI both analyzed mass shootings in public spaces. In these reports, the FBI and the Secret Service looked at the behaviors and backgrounds of active shooters involved in these attacks and presented some key findings, including their motivations, the weapons they used, and their history of violent behavior.

Based on what their analyses revealed, here are six common misconceptions about the perpetrators of mass shootings:


Myth: Mass shooters have a specific profile that can be easily spotted ahead of time.

Fact: There’s no one profile.

There’s “no useful profile of a mass shooter.”’

Marisa Randazzo, a former chief psychologist of the U.S. Secret Service and currently a managing partner at SIGMA Threat Management, discussed this with the public radio show 1A.

“There’s actually no useful profile of a mass shooter,” Randazzo said, “but there’s a lot we can look at in terms of behavior.”

For example, the FBI report referenced above finds that while the 63 active shooters examined in the study couldn’t be linked based on demographics alone:

62% of the shooters had a history of acting in an abusive, harassing, or oppressive way (e.g. excessive bullying, workplace intimidation); 16% had engaged in intimate partner violence, and 11% had engaged in stalking-related conduct.


Myth: They’re all mentally ill.

Fact: Only a quarter studied have been diagnosed with a mental illness.

University of Alabama Criminologist Adam Lankford says this is a common misconception about mass shooters.

According to the FBI report, only 25% of active shooters between 2000 and 2013 had ever been diagnosed with mental illness.

And according to a 2016 study published by the American Psychiatric Association, mass shootings by people with serious mental illness represent less than 1% of all yearly gun-related homicides.

It bears emphasizing: The vast majority of people with mental illness never commit violent crimes.


Myth: Mass shootings aren’t premeditated.

Fact: Most take a week or more to plan the attack.

The FBI researched 34 active shootings between 2000 and 2013 and found that in 77% of the cases, the subject spent a week or longer planning the attack.

“In this context, ‘planning’ means the full range of considerations involved in carrying out a shooting attack” according to the FBI report, such as making the choice to “engage in violence” and selecting targets.

The FBI researched 34 active shootings between 2000 and 2013 and found that in 77% of the cases, the subject spent a week or longer planning the attack.

The FBI researched 34 active shootings between 2000 and 2013 and found that in 77% of the cases, the subject spent a week or longer planning the attack.

The FBI researched 34 active shootings between 2000 and 2013 and found that in 77% of the cases, the subject spent a week or longer planning the attack.

Silver, J., Simons, A., & Craun, S. (2018). A Study of the Pre-Attack Behaviors of Active Shooters in the United States Between 2000 – 2013.https://www.fbi.gov/file-repository/pre-attack-behaviors-of-active-shooters-in-us-2000-2013.pdf/view/FBI

In its study, the FBI found that most shooters didn’t research target locations. Often, the shooters were already familiar with their intended target, such as their school or office.


Myth: There are no warning signs that can anticipate when someone might become violent.

Fact: There are behaviors that are a tip-off, including if those making threats have acquired firearms.

Mass shootings are extremely rare. They make up less than 1% of all U.S. gun homicides. It is hard to predict which individuals will actually become violent.

The FBI report notes that on average, each active shooter studied displayed four to five “concerning behaviors” over time that were observable to others around the shooter.

These include recklessness, violent media usage, changes in hygiene and weight, impulsivity, firearm behavior, and physical aggression.

In its research, the FBI found that in more than half the cases where “concerning behaviors” were displayed, the first behavior was reported over two years before the shooter carried out their attack.

The FBI found that in 56% of active shooters studied, the first concerning behavior was noticed over two years prior.

The FBI found that in 56% of active shooters studied, the first concerning behavior was noticed over two years prior.

Silver, J., Simons, A., & Craun, S. (2018). A Study of the Pre-Attack Behaviors of Active Shooters in the United States Between 2000 – 2013./FBI

In the Secret Service analysis, approximately half (48%) of shooters in 2018 had histories of criminal charges beyond minor traffic violations. About 30% had a history of domestic violence.

And just as in the FBI’s report, more than three-quarters (78%) of the attackers “exhibited behaviors that caused concern in others.”

These were observed sometimes by family members and also by strangers in their communities. Behaviors included social media posts with alarming content, inappropriate behavior toward females and writing about violence and weapons.


Myth: Mass shooters get their guns illegally.

Fact: Nearly 75% of the active shooters studied by the FBI legally purchased or possessed the firearm used in the crime.

Since 1982, there have been 114 mass shootings in the U.S., most of them involved guns bought legally.

Since 1982, there have been 114 mass shootings in the U.S., most of them involved guns bought legally.

Luis Melgar/Guns & America

Each state regulates gun possession differently. For example, a handful of states have laws barring people convicted of criminal stalking from purchasing a firearm. Others require owners to register certain “long guns” (a firearm fired while braced against a shoulder, like a shotgun or a rifle.)

Seventeen states and the District of Columbia now have so-called “red flag” laws that allow law enforcement or family members to petition the court for a temporary gun violence restraining order against an individual they believe is dangerous.


Myth: Mass shooters are motivated by violent media and video games.

Fact: There is no credible research that connects video game usage with violent behavior.

Following the mass shootings in El Paso, Texas, and Dayton, Ohio, President Donald Trump and several other prominent politicians blamed video game usage for the rise in these kinds of attacks.

In a White House address after the shootings, Trump said, “We must stop the glorification of violence in our society, this includes the gruesome and grisly video games that are now commonplace.”

Researchers have studied for decades whether playing video games is linked to violent behavior.

While there isn’t total consensus, the vast majority of research concurs that such a link does not exist. The American Psychological Association confirms this conclusion.

And the most recent UK study, reported on by Guns & America, reached the same conclusion: Researchers found no connection between playing video games and violent, aggressive behavior.

Even the late conservative Justice Antonin Scalia dismissed a link between violent video games and physical aggression back in 2011 in a California case involving selling those games to minors.

He wrote in that opinion, “these studies have been rejected by every court to consider them, and with good reason: They do not prove that violent video games cause minors to act aggressively.”

Editor’s note: This piece was adapted from a post published to Medium, July 5, 2018.

Guns & America is a public media reporting project on the role of guns in American life.