Palisades Charter High School was evacuated for about two hours due to a threat made against the school, LAPD said Tuesday morning.
The school began evacuations of classrooms around 9:30 a.m. Police investigated, and the bomb squad swept the campus, Officer Norma Eisenman said. Nearly 3,000 people, counting students and staff, were evacuated.
The apparent bomb threat was made via social media app Yik Yak, Eisenman said.
"It gives people freedom to post without fear of retribution," one parent said.
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The school was determined to be safe about 11:30 a.m. and students were allowed to return to campus, after being temporarily moved to Temescal Canyon Park.
Yik Yak is an app where users can post things anonymously, meaning users don't have a handle or a profile.
"It makes it difficult for people to decide ot they should take it seriously or not. Obviously they have to take it seriously," one parent told NBC4.
Nationwide, Yik Yak has been a platform for anonymous cyberbullying.
Yik Yak notes that it offers geo-fencing, which is way to deactivate the app in certain areas such as schools. Despite the geofence, a stream of Yaks were posted about the threat and the evacuation Tuesday, with one defiant stand stating "Yak will not be taken from us. We will stand together as one."
USC Annenberg digital journalism Prof. Robert Hernandez has been studying the Yik Yak phenomenon.
"It is truly interesting to see the engagement and the adoption rate," Hernandez said.
The school was also a polling place for Tuesday's election. Police moved the polling place to LA Fire Department Station #69 at 15045 Sunset Blvd.
Samia Khan contributed to this report.