An elementary school in Brentwood was briefly placed on lockdown Monday afternoon after someone called the school and talked about having a gun, police said.
The call was received around 2:25 p.m. in the administration office of Brentwood Elementary School, located at 200 Griffith Lane.
The caller disguised his or her voice and talked about having a gun at or near the school, according to police.
The students at the school were sheltered in place in their classrooms and the school and surrounding areas were searched by police and school district officials as a precaution, police said.
All students were safely released to their parents or taken home within an hour of the hoax call, police said.
Police are investigating who made the call and said they will seek the most serious charges possible against those found responsible.
Anyone with information about the case is encouraged to call Brentwood police at (925) 634-6911.