VISTA, Calif. — A North County education staff member is suspected of making an anonymous phone threat of violence that prompted the school’s campus to be placed on lockdown last month, authorities said.

Alma Cacho, 52, was arrested on suspicion of calling in the threat at Rancho Buena Vista High School in Vista using an app on their cell phone to disguise their location, Sgt. Alfred Gathings with the San Diego County Sheriff’s Department stated in a news release Thursday.

The incident occurred on Jan. 13 around 8:30 a.m. when the high school was placed on “secure campus” with students and staff safe indoors while authorities responded to the campus, the sheriff’s official said.

Deputies then conducted a security sweep of the campus and deemed the school safe. Classes also resumed as normal.

Investigators later determined the origin of the call was believed to be from Cacho, according to authorities. The case has been sent to the San Diego County District Attorney’s Office for prosecution.

“In recent months, the Vista Sheriff’s Station has responded to several school threats. Multiple suspects were identified in these cases. The Sheriff’s Department works directly with the District Attorney’s Office to prosecute these crimes,” Gathings said.

Students who hear about any threats or even potential violence are advised to approach the sheriff’s school resource deputies or call the anonymous Student Speaking Out Hotline at (888) 580-8477.