Officers responded Friday to Blair High School in Pasadena after a report of a person with a gun on the campus. At least eight squad cars were at the school, which remained on lockdown at noon.
Around 12:45pm, CNN showed live video of students being evacuated, with hands held on their heads.
The classroom-by-classroom search was continuing at the school, which is located at 1201 S. Marengo Ave., at about 1 p.m., the dispatcher said. So far, there has been no sign of anyone with a weapon.
1:32pm: While some news reports are that students being allowed back into the school, live video is showing long lines of students being moved out of the school, with hands against the back of their heads, and being led into another building on campus, possibly the gymnasium.