A report of a man yelling in the street near Stevens Creek Boulevard and Orange Avenue in Cupertino last week ended with deputies uncovering a Glock-style ghost gun rigged with a full-auto conversion switch, tucked inside a black bag the man had tried to ditch as they arrived.
According to a post from the Santa Clara County Sheriff's Office
, West Valley Patrol deputies responding to the disturbance call watched the man attempt to tuck the bag under his arm and slip behind a row of nearby buildings. When he reappeared on the sidewalk, the bag was gone. Deputies tracked it down and, inside, found the ghost gun with one round already in the chamber, a full-auto switch attached to the rear of the slide, and several more rounds loaded in the magazine. The man was taken into custody and booked on several felony charges, the sheriff's office said.
How a Backyard Switch Turns a Handgun Into a Machine Gun
How a Backyard Switch Turns a Handgun Into a Machine Gun The device deputies say they found on the gun is commonly known as a Glock switch, a small attachment that can convert a semiautomatic handgun into a machine gun. Federal law and Bureau of Alcohol, Tobacco, Firearms and Explosives regulations classify these conversion devices as machine guns in their own right under 26 U.S.C. § 5845(b), meaning unauthorized possession can bring up to 10 years in federal prison under 18 U.S.C. § 922(o), according to the U.S. Department of Justice. The federal guidance classifies the conversion devices themselves as machine guns.
California law adds its own layer of exposure. Under Penal Code Section 32625, possessing or knowingly transporting a machine gun is a felony punishable by county jail time or a fine of up to $10,000, while intentionally converting a firearm into a machine gun can carry a state prison sentence of four, six, or eight years, per Justia Law. State law defines a machine gun broadly as any weapon that fires more than one shot automatically without manual reloading from a single trigger pull. Separately, ghost guns like the unserialized Glock-style pistol described in the sheriff's post are already illegal to possess in California under Assembly Bill 1621, enacted in 2022, which banned unserialized firearm frames and receivers statewide, according to LegiScan.
Part of a Broader Local and National Crackdown
Part of a Broader Local and National Crackdown The Cupertino find lands amid what federal data describes as a sharp rise in these devices nationwide. ATF figures show a 570 percent increase in firearms recovered with machine gun conversion devices between 2017 and 2021, according to the Center for Governance and Information Technology. Closer to home, the Santa Clara County Gun Violence Task Force is focused on gun violence.
This is not the first time West Valley deputies have pulled an untraceable firearm off Cupertino streets. In March 2025, a San Jose traffic stop involved a juvenile and an adult, as Hoodline reported. Regionally, the Santa Clara County District Attorney's Gun Violence Task Force addresses gun violence.
The sheriff's office has not released the suspect's identity, the specific felony counts filed, his bail status, or whether the case will proceed through local or federal prosecutors. What deputies have confirmed is that a routine call about a man yelling in the street turned up a weapon capable of fully automatic fire on a stretch of Stevens Creek Boulevard that residents cross every day.
