What Is A Patrol Rifle? Alleged Gun Used in Boulder Shooting

The mass shooting at a King Soopers supermarket in Boulder, Colorado, that left 10 people dead, including a police officer, on Monday, has reignited debate surrounding gun control after the suspect was alleged to have used a patrol rifle during the attack.

About 2:30 p.m. local time on Monday afternoon officers responded to a call about "a possible person with a patrol rifle," Boulder Police Chief Maris Herold told reporters.

A shirtless man was captured by KMGH footage in handcuffs as he was led away by officers, with authorities later confirming a suspect had been taken into police custody.

Police have yet to release information about how the shooter acquired the gun or what the motives were behind the attack.

However, a law enforcement source told ABC News that responding officers arrived at the scene to find a suspect "carrying a long gun" who "opened fire on them."

Law enforcement officials briefed on the investigation said the suspect used an AR-style rifle in the attack, the Wall Street Journal reported. One senior law enforcement source further clarified to CNN that the weapon used was an AR-15 style rifle.

Rest In peace Officer Eric Talley. Your service will never be forgotten #BoulderShooting pic.twitter.com/FVximvhS2E

— Boulder Police Dept. (@boulderpolice) March 23, 2021

Patrol rifles are the firearms most commonly employed by tactical units and are often carried by police officers on patrol, according to a report in the International Journal of Police Science and Management.

The National Institute of Justice 2019 report on Patrol Rifles for Law Enforcement describes these weapons as "semiautomatic or have semiautomatic firing mode and magazine-fed" and are designed and intended to be fired from the shoulder using the energy of the explosive in a fixed metallic cartridge to fire only a single projectile through a rifled bore for each single pull of the trigger.

The AR-15 rifle cited by Boulder law enforcement officers to have been used in Monday's shooting hit the market in the early 1960s as the first civilian version of the military's M16 rifle.

The lightweight semiautomatic rifle became one of the "most beloved and most vilified rifles" in the nation in the 2010s and "was popularized by the rise of a video game culture," according to The New York Times.

The weapon has since become synonymous with mass shootings throughout the U.S. and was reportedly used in several high-profile incidents including the 2012 Aurora, Colorado movie theater mass shooting and the slaughter of 20 children in an attack in the Sandy Hook elementary school in central Connecticut in the same year.

AR-15 rifle
File photo: An AR-15 is seen for sale on the wall at the National Armory gun store on January 16, 2013 in Pompano Beach, Florida. Joe Raedle/Getty Images

AR-15s or similar rifles were the primary weapons used in around half of the 10 deadliest mass shootings in modern American history, the Los Angeles Times reported in February of 2018.

Colorado has seen a spate of these high-profile incidents including the 1999 Columbine High School massacre, the 2012 Aurora movie theater mass shooting and the 2015 Planned Parenthood shooting.

The violence led to increased gun safety reforms, including universal background checks, a large capacity magazine ban and a "red flag" law that allows weapons to be temporarily seized from those deemed an extreme risk.

The state is currently rated a "C+" on the Annual Gun Law Scorecard from the Giffords Law Center, a group that advocates for tighter gun control.

Monday's attack is the second mass shooting in the U.S. this year alone and has culminated in a renewed call by Democrats for gun control reforms.

A mass shooting, as defined by the Mother Jones Mass Shootings Database and shown in the graph below by Statista, is an incident where a minimum of 3 people are shot and killed by lone shooters, excluding the perpetrators, in public places over short periods of time.

Mass shootings in U.S. - Statista
The number of mass shootings in the U.S. recorded each year as displayed by Statista. Statista

Boulder Police Chief Maris Herold said officers would "work around the clock" to ensure justice was served.

"This is a very complex investigation that will take no less than five days to complete," she told reporters on Monday night.

Boulder County District Attorney Michael Dougherty described the incident as "a tragedy and a nightmare for Boulder County."

"These were people going about their day, doing their shopping. I promise the victims and the people of the state of Colorado that we will secure justice," he said.

Newsweek contacted the Boulder Police Department for comment.

Police Guns
File photo: A Los Angeles Police Department officer displays recovered guns from residents turning in firearms across Los Angeles, California on December 5, 2020. Law enforcement officials briefed on the investigation said the suspect used an AR-style rifle in the King Soopers attack in Boulder, Colorado. Frederic J. BROWN/Getty Images

Update 3/23/21, 9:30 a.m. ET: This article was updated to include an infographic.