(NewsNation) — A shooting at an Indiana mall Sunday that left three innocent people dead and two more injured could have been far worse if not for the actions of an armed civilian, authorities say. Police are calling 22-year-old Elisjsha Dicken a hero after they say he shot and killed the suspected 20-year-old gunman with a firearm he was legally carrying.

“Many more people would have died last night if not for a responsible, armed citizen that took action very quickly within the first two minutes of the shooting,” said Greenwood Police Chief Jim Ison.

How common is it for civilians to stop active threats? Data from the Advanced Law Enforcement Rapid Response Training (ALERRT) Center at Texas State University suggests bystanders stop active attacks about 16% of the time, although typically without using a gun.

From 2000 to 2021, ALERRT researchers studied 464 attacks (434 shootings, 23 knife attacks, and seven vehicle attacks) and found civilians—including security guards and off-duty police officers—stopped attackers before police arrived on 73 occasions. In the vast majority of those cases (67%), bystanders subdued the assailant using physical force. An armed civilian stopped attacks using a gun in 24 of the 464 attacks recorded, about 5% of all events. Of those 24, only half were civilians—the rest were security guards and off-duty police officers.

ALERRT researchers found police stopped attackers about twice as often as civilians, doing so in about 31% of all incidents. In approximately 42% of the cases studied, the attacker stopped on their own before police arrived, either leaving the scene or killing themselves.

“Properly trained folks with a high level of vigilance are able to sometimes, in very rare circumstances, support public safety in those moments,” said Phil Andrew, a NewsNation contributor and former FBI agent. He pointed out that even with Dicken’s rapid response, three people were killed, emphasizing that the best prevention strategy is one that stops bad guys from getting a gun in the first place.

Others said Sunday’s intervention is further evidence that law-abiding citizens can and should be able to carry guns. “Don’t just go buy a gun because you’re afraid—train with it, know how to make good decisions, know what the law is in your state,” said retired Sgt. Betsy Brantner Smith, a spokesperson for the National Police Association. “This young man clearly knew all of those things … We believe he’s a hero.”

In Indiana, Ison said surveillance footage showed Dicken engaging the gunman from “quite a distance” with a handgun. The chief said Dicken had no police training or military background, as far as officials know.

“There’s been this statement: ‘The only thing that stops a bad guy with a gun is a good guy with a gun,’” said Adam Lankford, a criminal justice expert at the University of Alabama who has written books and research papers about mass shootings. “That’s factually inaccurate because of the word ‘only.’”

Nonetheless, gun-rights advocates, including the National Rifle Association, used that phrase on social media to draw attention to what happened in Indiana. Since July 1, the state has allowed anyone 18 or older to carry a handgun in public, though private property owners can prohibit firearms. The Greenwood Park Mall has a ban on weapons, according to its conduct code.

Gun Owners of America hopes the mall reconsiders, saying gun-free zones create a false sense of security. The Greenwood mall, owned by Simon Property Group, didn’t reply to a request for comment but released a statement commending first responders and the “heroic actions of the good Samaritan who stopped the suspect.”

Lankford believes that it would be a mistake to think that armed civilians can be relied upon to regularly stop mass shootings. “While it’s certainly a good thing in this mall shooting that someone was able to stop it before it went any further, let’s not think we can substitute that outcome in all past and future incidents,” he said. “If everyone’s carrying a firearm, the risk that something bad happens just gets much larger.”

Smith acknowledged that trying to stop an active shooter comes with considerable risk, both from the attacker and in some tragic cases, responding law enforcement who may have trouble determining the true threat. Last year, police in Arvada, Colorado shot and killed 40-year-old Johnny Hurley after he was mistaken for an active shooter. Just moments earlier, Hurley had brought down the actual gunman with a handgun he was legally carrying.

As part of her training, Smith teaches police officers how to communicate and comply in situations where they may be accidentally perceived as a suspect while intervening off-duty. When asked whether civilians may feel more compelled to engage active shooters following law enforcement’s highly publicized failures in Uvalde, Texas, Smith and Andrew agreed that the response at Robb Elementary was atypical and not representative of most departments.

There have been other examples of armed people defending large groups. In May, a woman fatally shot a man in Charleston, West Virginia, after he fired an AR-15-style rifle into a crowd at an outdoor party. She was praised by police, but not charged. In 2017, Devin Patrick Kelley crashed his car and killed himself after bystanders, including one who was armed, chased him after he massacred 26 people at a church in Sutherland Springs, Texas.

The Associated Press contributed to this report.