An underground "machine gun marketplace" operating on social media has become a steady pipeline of illegal firepower into Chicago, and federal agents say one undercover buy this week shut down at least one seller. Authorities arrested a 20-year-old identified in court filings as Aiden Alejandro after an operation that investigators say caught him negotiating and completing a sale that included a conversion device to make a pistol fire automatically. The case shows how tiny parts and coded messages are changing the way weapons move on and off Chicago streets.
According to investigators, Alejandro used coded Facebook messages to arrange a deal for three firearms and a machine-gun conversion kit, then calmly counted the cash after the sale, unaware the buyers were undercover agents. Undercover video captured the transaction, and Alejandro was arrested. Prosecutors say he now faces federal charges for possession and transfer of a machine gun and is being held without bond at the Metropolitan Correctional Center in Chicago, with a preliminary hearing set for next Tuesday. NBC Chicago reports Alejandro was earlier arrested in 2024 on a machine-gun charge that Cook County prosecutors dropped after he pleaded guilty to being a felon in possession and was placed on court supervision. If convicted in federal court he faces up to ten years behind bars, according to NBC Chicago.
"As a survivor of gun violence, I know that behind every statistic is a person, a family, and a community whose life has been forever changed," Leona Daley said at a City Hall event where Mayor Brandon Johnson unveiled a new Gun Violence Reduction Office. The announcement landed as Chicago police data showed almost 25,000 illegal guns had been removed from the streets over the past two years, roughly 35 a day, a number investigators say increasingly includes pistols modified for nonstop fire, NBC Chicago reports.
How traffickers use social media
Traffickers often post weapons and accessories on Facebook and Instagram, then steer interested buyers into private or coded messages to set up cash handoffs and quick meetups. ATF officials say undercover buys, surveillance, and scouring social-media accounts have become central tools in recent stings that recovered conversion devices and fully automatic weapons, showing how a casual-looking post can translate into serious street-level firepower. The ATF said those operations led to arrests and prosecutions across multiple states.
Federal prosecutions highlight the threat
Prosecutors in the Chicago area have leaned on undercover buys and digital forensics in trafficking cases before. In 2023 the U.S. Attorney’s Office for the Northern District of Illinois indicted a suburban man accused of selling 25 "Glock switches" and a 3-D printer used to manufacture them, noting each count carries a maximum penalty of up to ten years in prison. Those prosecutions are part of a Project Safe Neighborhoods enforcement push that coordinates ATF, U.S. attorneys and local partners to choke off supply routes, according to the U.S. Attorney’s Office, Northern District of Illinois. Local reporting has tracked similar enforcement, including a recent Glock switch bust in the region.
Legal stakes
Under federal law a conversion device, the small "switch" or auto-sear, is treated as a machine gun in its own right, and possession or transfer is a felony under the Gun Control Act and the National Firearms Act. That prohibition can bring maximum penalties of up to ten years in prison and steep fines, and prosecutors can seek longer sentences when conversion devices are tied to violent or drug offenses. The federal statutes in U.S. Code Title 18 and Title 26 that spell out the definitions and penalties are collected by the Legal Information Institute.
Authorities say the Alejandro arrest underscores why prosecutors and the new city-level office are trying to cut off supply lines as aggressively as they prosecute shooters. Joint task forces say undercover work, tracing and interagency prosecutions remain the most effective tools against online arms dealers, and investigations tied to this case are ongoing.
