A 22-year-old man was arrested on suspicion of possessing a "ghost gun" in San Marcos, authorities said Saturday.
Neighbors called law enforcement just after 11 p.m. Friday to report a group of suspicious people in the 500 block of Spanish Oak Avenue, said Sgt. Nicholas Arvanitis of the sheriff's San Marcos station.
Deputies contacted four people hanging around a pickup truck, Arvanitis said.
"During the contact, a handgun loaded with bullets were clearly visible on the passenger seat," he said. "The firearm turned out to be a ghost gun."
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Tristan Banuelos, the driver of the pickup truck, was arrested on suspicion of carrying a loaded gun in a public place or public street and owning or possessing a gun without a serial number, he said.
"Unlike weapons made by a licensed manufacturer, ghost guns don't have a serial number or other identifiable markings," Arvanitis said.
"The lack of a serial number makes it extremely challenging for law enforcement agencies to track these firearms to their owner or maker, hindering or delaying investigations and crime-solving efforts."