Rancho Buena Vista High School
Rancho Buena Vista High School. Photo via @RBVHighSchool Twitter

A staff member at a Vista secondary school was arrested this week on suspicion of issuing an anonymous threat of violence at the campus, authorities reported Thursday.

Alma Cacho, 52, allegedly made the threat against Rancho Buena Vista High School on Monday morning via a cellphone app designed to disguise the origin of the call, according to the San Diego County Sheriff’s Department.

Administrators at the Longhorn Drive campus kept all students and employees secured indoors while deputies conducted a security sweep of the grounds and facilities, sheriff’s Sgt. Alfred Gathings said. Once the school was deemed safe, classes resumed as normal.

Cacho was identified as the alleged perpetrator of the crime after investigators “were able to locate the origin of the call and determine the caller was a staff member,” Gathings said.

Officials did not reveal details about the purported threat, disclose a suspected motive or identify the nature of Cacho’s job at the school.