Marquist Evans was standing at the counter of a 7-Eleven on the West Side when two men rolled up in a Jeep and began firing at the car he was in moments earlier, federal authorities say.Evans pushed open the front door of the store, aimed his own .40-caliber Glock pistol at the gunmen standing near some gas pumps and fired a 1.5-second burst of bullets, according to prosecutors. They say the masked gunmen fled in the Jeep, and Evans sped away in the car. It’s unclear whether either of the gunmen was hit in the May 6 shootout. But the Jeep was struck, which a security camera captured, and the glass storefront was riddled with bullets.Evans was later arrested and charged with possession of a machine gun because, according to prosecutors, the pistol he was carrying was equipped with a small device called a switch that illegally converts handguns into automatic weapons that continuously fire with a single trigger pull.The police said they recovered 33 bullet cartridge cases near the front door of the 7-Eleven in the 500 block of West Grenshaw Street and think all of those brass casings came from Evans’ .40-caliber handgun.During an appearance at the City Club of Chicago last month, Christopher Amon, head of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives in Chicago, pointed to the 7-Eleven shootout as an example of an increasingly dangerous problem for the city: the proliferation of switches.“We have seen an alarming rise in these devices,” Amon said, noting that the Justice Department and his office, which operates a new, multi-agency intelligence center in the Loop have put a new focus on cracking down on their possession.“This is something that didn't exist four years ago,” he said. “The rise of these devices started about 2019." Christopher Amon, special agent in charge of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives in Chicago.Tyler Pasciak LaRiviere / Sun-Times Machine guns were "basically outlawed in this country because of what was happening in Chicago" in the 1920s with the Thompson submachine gun — the Tommy gun — that was being used in gangland warfare across the city, Amon said.The modern-day use of handguns equipped with automatic switches — as detailed in a Chicago Sun-Times investigation in 2022 on the growing danger the devices are posing on Chicago's streets — has continued unabated since then.That's the picture revealed by a variety of measures — from interviews, from the steady rise of mass shootings in Chicago and from the growing number of arrests in Chicago of people caught with switches.The University of Chicago Crime Lab says switches, along with high-capacity magazines that hold bullets, have dramatically increased the lethality of shootings. That’s because they let a shooter fire more bullets far more rapidly — and hit their targets more often. Related In Chicago, handguns easily turned into high-capacity machine guns fuel growing violence How high-capacity magazines for weapons have become a mass-market item One in seven people died of bullet wounds in 2010 in Chicago. Now, the rate is closer to one in five, according to the crime lab’s research.The lab says the worsening gunshot fatality rate is linked to another disturbing statistic: About 15 years ago, only 1% of shooting scenes in Chicago yielded more than 20 bullet casings. Now, that number is 16%, the lab says.Authorities say they believe that switches have been used with the guns that killed three law enforcement officers in the past two years: Chicago police officers Areanah Preston and Luis Huesca and Cook County Sheriff’s Deputy Rafael Wordlaw. The man who shot Wordlaw fired almost 70 rounds, according to the police.“We had a couple of officers who were victims of weapons that had switches,” Chicago Police Department Supt. Larry Snelling says. “And it only makes me think of our family members, your family members, people who could come in contact with someone who wants to rob them, who's armed with a weapon like that. It's very dangerous. And we have to have some type of control over this.”Snelling says officers often find 30 to 40 bullet casings after shootings — the result of this illegal automatic gunfire.“That is absolutely insane when you think about it," Snelling says. "And it's very dangerous for everyone, especially with large gatherings. You hear about these mass shootings, and a lot of it has to do with that." A photo from the city of Chicago’s lawsuit against Glock, Inc. that argues that thegun-maker’s handgun designs make it easy for people to install illegal devices known as switches on them. Glock doesn’t make the switches, but the underground-market devices often come with a forged company logo on them.City of Chicago v. Glock, Inc. Experts say the combination of switches and extended ammunition magazines — which are illegal to sell or possess in Chicago and suburban Cook County but sold legally in many other places and easily available online — have become must-haves among gangs and even seen as glamorous. Popular rappers have featured the devices in their songs.The switches are easy to get and difficult for authorities to intercept. They’re often shipped from China, disguised as machine parts. They also can be made in the privacy of anyone's home with a 3D printer. Source: Cook County state’s attorney’s office Still, more and more people in Chicago are getting arrested for possessing and selling switches. According to the Cook County state's attorney’s office, 69 people were charged in machine-gun cases in 2021. Most of those cases involved having a gun equipped with a switch. The number of these cases has steadily gone up over the past three years in Cook County, with 311 people charged and 138 convictions last year and 268 people charged this year, as of Sept. 25.Federal authorities have had only a handful of cases that involve specific machine-gun charges in Chicago over the past few years. But law enforcement sources say the small number might be misleading because federal prosecutors often decide to charge people caught with switches under broader criminal conspiracy and gun laws. Anthony Prisco.Cook County Sheriff’s arrest photo In one unusual legal situation, a young south suburban man, Anthony Prisco, was hit with both state and federal machine-gun charges in separate cases.Prisco, of Oak Forest, pleaded guilty to a state machine gun charge after Cicero cops caught him with three switches in 2022. He was given probation because he was only 19 at the time, and it was his first offense. Soon, though, he got in trouble again, with federal as well as state authorities.In 2023, the ATF opened an investigation of Prisco and said that, between June 15 and June 20 that year, he sold an undercover agent 25 switches, a handgun and a 3D printer the agency said Prisco was using at home to make switches. Prisco sold all of it to the agent for $2,800, according to the ATF.The agency says that, at one meetings, the undercover agent told Prisco, “Anything to make my Glock go full auto, I love it, bro,” and that Prisco replied, “Hell, yeah, that’s what’s up.”On June 24, 2023, Prisco was arrested by the Oak Forest police on charges of possession of a gun, fentanyl and other kinds of drugs. That case has been dismissed.But the next month, as Prisco was still in jail in that case, he was indicted by a federal grand jury on a machine-gun possession charge related to the ATF investigation. Agents said they found switches at his home, including two they said he admitted were for converting AR-type semi-automatic rifles into fully automatic machine guns. On Oct. 3, he pleaded guilty. Still to be sentenced, he faces up to 10 years in prison.The Justice Department has said earlier this year that cracking down on switches would be a top priority for the government.Across the country, federal prosecutors have launched anti-switch initiatives with names like “Operation Kill Switch” and “Operation Flip the Switch.” In September, federal authorities said they had seized more than 350 internet domains suspected to be linked to the illegal importation of switches and silencers from China in packages labeled as “toys” and “necklace.”In Chicago, the ATF has opened a Crime Gun Intelligence Center to work with other agencies — including the FBI, the Chicago police and the Illinois State Police — to test guns, bullets and bullet casings recovered from crime scenes and to use advanced technology to link them to other shootings. Almost half of those switch-equipped guns have been linked to one or more shootings through testing, according to the ATF, which says it can use that information to investigate patterns of violence, including mass shootings. A security camera caught this image of a masked gunman (right) firing toward Marquist Evans, who was standing in a 7-Eleven in the 500 block of West Grenshaw Street on May 6.U.S. attorney’s office In its own legal battle against switches, the city of Chicago is suing gun-maker Glock, saying the company is endangering people in Chicago because its handguns are manufactured in a way that makes it easy to attach switches to them. Glock has denied doing anything illegal.In the same civil case filed in Cook County circuit court, the city also is suing two suburban gun stores because they’re on a “preferred roster” of Glock dealers, according to the city.