Champs Charter High School on alert after online threat

VAN NUYS, LOS ANGELES (KABC) -- Extra security was on hand Friday at Champs Charter High School in Van Nuys because of threats on social media.

The threat was posted on Yik Yak, an anonymous social networking site.

The Los Angeles Police Department is trying to find out who put out the threat.

Officials say there is no way to tell if the threat is credible, but the school and police are taking extra precautions. Classes continued as scheduled on Friday.