Machine Gun, Grenade Launcher Seized In Foster City Weapons Bust

FOSTER CITY (CBS SF) – A man has been arrested after authorities seized illegal weapons at a Foster City home, including a machine gun with a grenade launcher.

According to the Contra Costa County Sheriff's Office, deputies with the CASE Team arrested 41-year-old Joseph Holmes last Thursday without incident while executing a search warrant at his home on the Peninsula.

Deputies said they were following a tip that Holmes allegedly obtained Glock conversion switches, which allow pistols to fire in full automatic mode, making them illegal machine guns.

The seized items include four Glock conversion switches, three AR-15 assault rifles, a machine gun with attached silencer and grenade launcher, along with nearly two dozen large-capacity magazines.

Holmes faces multiple charges, including possession of a machine gun, possession of an assault rifle, manufacturing an assault rifle, possession of a silencer, possession of a destructive device, illegal transfer of a firearm, importation of large capacity magazines and possession of an explosive agent.

Deputies said their investigation will be forwarded to the Contra Costa District Attorney's Office for prosecution.