SPRING VALLEY, Calif.—Five people were arrested Tuesday in connection with a suspected human smuggling operation in San Diego County.

About 7:35 a.m., U.S. Border Patrol agents assigned to the San Diego sector were notified of a suspicious vehicle involved in a suspected human smuggling event in progress on Otay Lakes Road near Otay Lakes.

“The suspect vehicle was observed proceeding to an apartment complex on Rosedale Drive in Spring Valley before several occupants exited the vehicle and attempted to flee on foot,” according to a statement from Michael J. Scappechio, public affairs specialist with the U.S. Customs and Border Protection (CBP) Media Division, San Diego Office. “Responding Border Patrol agents who arrives at the scene reported hearing a noise consistent with a single gunshot not long after the occupants exited the vehicle.”

Scappechio said Border Patrol agents, after a brief search, placed five individuals in custody.

“Four were suspected of being undocumented migrants, and a U.S. citizen was suspected of driving the vehicle,” he said.

The five people taken into custody were not identified by the Border Patrol.

San Diego County Sheriff’s Department said there were initially some erroneous reports that a helicopter had been circling over the Spring Valley apartment complex following a shooting involving law enforcement. Scappechio said no law enforcement personnel at the event scene discharged their firearms. CBP said no weapons were found at the scene, and it was unknown if any shot was actually fired.

The Border Patrol seized the suspect vehicle.