Students at Moorpark High School were dismissed early Thursday after a threatening note prompted a school lockdown and at least two campus searches by authorities.
School officials notified the Ventura County Sheriff's Department about 8:20 a.m. after the note, written by a student, was found on campus, said sheriff's Capt. Don Aguilar.
Details of the note's contents were not known, but Aguilar said it included some type of "threat to harm." The person who found the note notified school officials "immediately," Aguilar said, and deputies were on scene within minutes as the campus was locked down.
Roughly 70 sheriff's deputies, a bomb squad and K-9 unit searched the campus but found no explosives, Aguilar said. At about 11 a.m., officials said students would be released for the day as authorities conducted a second precautionary search.
No injuries have been reported.
Students were being moved through cleared areas of the campus and released to their parents "in an orderly fashion," Aguilar said. Officials announced shortly before 11:45 a.m. that all students had been safely evacuated.
Aguilar said about 2,200 students attend the high school.
Nearby Arroyo West and Mountain Meadow elementary schools were also locked down as a precaution, sheriff's officials said. By 11:45 a.m., normal operations had resumed at those schools.