Police investigate possible 'threat of violence' at San Ramon high school

Police in San Ramon responded to a possible threat of violence aimed at a local high school Wednesday afternoon, authorities said.

"Nothing suspicious" was found after officers searched the California High School campus, police said. 

Police planned to maintain a "heavy presence" at the school until students departed.

Authorities had not specified what was the nature of the threat.

"Our agency is aware and investigating a threat of violence," the San Ramon Police Department said in an earlier tweet. "As a result, multiple officers are now on campus conducting a thorough security check of the school and surrounding area."