When Alonzo Velasco sold an undercover officer machine-gun conversion devices outside his Chicago apartment building in the summer of 2023, he pointed out that he could get more — a whole lot more.
According to federal prosecutors, Velasco delivered the officer nearly 20 tiny “switches” that turn handguns into fully automatic weapons that can fire multiple rounds with a single trigger pull. They’ve been used in many mass shootings here in recent years.
In a series of deals, the officer paid $5,250 for the switches, and Velasco said he could get dozens more from his supplier, according to court records. He also explained how the switches can turn handguns into “choppers,” slang for machine guns, the complaint said.
A few months after those deals, Velasco was sentenced to state prison for a separate Cook County gun possession conviction.
Velasco, 26, who pleaded guilty last month to a federal charge of unlawfully transferring a machine gun, faces up to 10 years in federal prison for the crime. Prosecutors say they anticipate he could get at least 18 months behind bars under federal sentencing guidelines.
He’s among the 41 people ensnared in a two-month-long investigation led by the Chicago Police Department and federal Bureau of Alcohol, Tobacco, Firearms and Explosives, authorities said Tuesday.
The investigation resulted in the recovery of 64 switch devices and 171 guns, many of which were linked to shootings, killings and other “violent criminal activity” dating back to 2017. The switches, officially known as “auto sears,” are also called buttons on the street.
Alec Chisolm-Blockton, 29, was on parole for fatally shooting a 14-year-old boy in suburban St. Louis when he was caught selling three guns to undercover officers this summer. He now faces a federal charge of possessing a gun as a felon, court records show.
Another man, Eddie Arguelles, was charged in Cook County criminal court in May with firing a switch-equipped gun at the Riis Park football field, court records show. Arguelles, 20, tried to flee police on a scooter but was taken down by an officer and arrested.
Between 2019 and 2023, there was a 784% rise in the number of switches recovered by law enforcement, according to the ATF. Last year, Chicago police recovered 604 of the machine-gun conversion devices — up from 81 in 2020.
In a statement, U.S. Attorney Andrew Boutros said the devices “pose a grave threat to public safety.” Boutros said his office “will lean into using various federal law enforcement tools and law enforcement partnerships to hold firearm offenders accountable and reduce violent crime in Chicago.”
Some of the 41 cases will be prosecuted in federal court and the others in Cook County criminal court. The investigation was led by ATF’s Crime Gun Intelligence Center, which opened last year in Chicago.
At the time, Deputy U.S. Attorney General Lisa Monaco told reporters that 13 federal, state and local law enforcement agencies would be working together inside the center to target people suspected of being prolific gun offenders.