Students and employees at Hillsdale High School at 3115 Del Monte Street in San Mateo were evacuated to nearby Abbot Missle School. According to the CHP, there are reports of a pipe bomb inside the high school. KRON 4 reports that a suspect has been arrested.

One student, Cody, who was interviewed by KRON 4 News, says he saw a student "run down the hall" while trying to light pipe bombs and throw them. Then, another overexcited teenager tells KRON 4 that she heard people got shot and heard they brought in chainsaws too. (This wasn't actually the case, the shooting -- but, God, we LOVE teenagers.) He also heard an explosion. No reports of any injuries.

CBS 5 have a chopper live on the scene.