Classes at Mira Costa High School resume with heightened security

MANHATTAN BEACH, Calif. (KABC) -- As classes resumed at Mira Costa High School on Thursday, new security measures were in place in response to threats posted on social media.

Police presence was high on campus all day. Students were allowed to enter the campus through four approved locations. Several other gates around the campus that are usually open were locked.

Students were advised to leave their backpacks and bags at home, so many arrived carrying books and binders in hand. Those who brought bags and backpacks had them searched before passing through the gates.

Also, school officials outlined some strict guidelines to keep students inside their classrooms throughout the day, so students are not wandering around the school. These guidelines and new security measures were emailed to parents on Wednesday.

"I just feel unsafe. I don't know. I feel like if they're having to take these extra measures for us to feel safe at school, we shouldn't come to school," said Blake Bordokas, a senior at the school.

The school has been closed since Tuesday, following a lockdown on Monday. That's when school administrators were made aware of a criminal threat posted anonymously to a social media app called Yik Yak.

The threat stated: "If you go to Costa you should watch out very closely at school today." A second anonymous message was posted later Monday afternoon: "nice try costa, today was just a drill."

"Something like this should definitely be taken seriously," said Bella Bethoney, a senior at the school. "It's not funny."

On Wednesday, Manhattan Beach police identified a female juvenile as the individual who posted at least one of the threats. Authorities said she and her parents were interviewed by investigators, but the girl was not arrested.

Police said she did not attend Mira Costa High School. In fact, officials said she did not attend any school in the Manhattan Beach Unified School District.

"Nothing is truly anonymous. I believe the message is, if you're going to post something like that, be prepared for the consequences, particularly legal and criminal consequences, for that," said Manhattan Beach Unified School District Superintendent Michael D. Matthews.

Matthews said backpack checks and other security measures will likely continue Friday, which is the last day of school before Thanksgiving break.

Investigators are still working to identify any other potential suspects tied to the threats. Anyone with information was asked to call officials at (310) 802-5140.