Just as about 4,000 Arcadia High School students were preparing to go home for the day on Thursday, Sept. 12, Arcadia Police ordered a lock-down of the entire campus for more than three hours in response to a phoned threat of a mass shooting.
Police received an anonymous call at 2:38 p.m. warning that the caller was at the school and that he was going to start shooting students with an assault rifle. Police officers arrived at the campus and the school was placed on lockdown while a systematic search was conducted.
Much of Duarte Road and Campus Drive were block for more than two hours during the lockdown, with police and news helicopters circling overhead, and causing concern and traffic congestion by parents arriving to pick up their children.
Just as the lockdown was about to be lifted around 5 p.m., a second call was received, during which the caller told the officers to back off or they would get shot. The search continued and no suspects or weapons were found, but students and parents were forced to wait even longer as rush hour traffic increased congestion in the area.
Shortly before 6 p.m. the lockdown was lifted and the students were dismissed one room at at time and loaded on buses and shuttled down the street to the east side of the County’s Arcadia Park where parents had been directed to park and wait for their children. But parking in the park was soon filled to capacity and parents were then instructed to park on side streets. By about 6 p.m., in order to expedite the process, students were escorted by officers on foot to Arcadia Park.  The final group of teachers and others were released about 6:45 p.m.
The Arcadia Police Department is conducting a collaborative investigation with allied agencies and the FBI as this incident is similar to others recently occurring in the area.