SPRING VALLEY — A threatening phone call prompted a campus lockdown at Monte Vista High School in Spring Valley on Monday, though authorities said the threat was ultimately not credible.

School administrators notified a school resource deputy after receiving the call shortly after noon at the campus on Sweetwater Springs Boulevard. The school was immediately placed on "secure campus" status, requiring students and staff to remain inside classrooms with doors locked while instruction continued.

Deputies from the San Diego County Sheriff's Rancho San Diego Station responded to the campus and remained on site as detectives investigated. According to the sheriff's office, the investigation linked the call to multiple similar incidents reported over the previous two weeks by other law enforcement agencies in California and Idaho — all involving the same phone number and the same wording.

"All evidence indicates the threat was not valid," the sheriff's office said in a statement. "There is no present threat to the school, students or staff."

Deputies continued to patrol the campus as a precaution while normal school operations resumed. Detectives are working to identify the person responsible for the calls. Parents of Monte Vista students may contact the Rancho San Diego Sheriff's Station with any information.