Phone threats against Guajome Park Academy prompted an approximately 90-minute lockdown of the campus Friday while authorities investigated.
The kindergarten-through-12th-grade school in the 2000 block of North Santa Fe Avenue in Vista received the menacing calls about 12:30 p.m., according to the San Diego County Sheriff's Department.
Administrators secured students and teachers in their classrooms while deputies searched the campus and surrounding neighborhood by ground and air.
The personnel found nothing out of the ordinary in the area and gave an all-clear about 2 p.m.
Because the school targeted by the threats was on a half-day schedule, most students had gone home by the time the security alert began, officials said.
Deputies escorted the few youths still on campus to their parents.
Officials did not disclose what the unidentified caller or callers said to initiate the emergency measures.