CORONA, Calif. (KABC) -- Centennial High School in Corona canceled all classes Tuesday due to a bomb threat, which authorities said was an apparent hoax.
According to Corona police, dispatchers received a phone call on a non-emergency line regarding a bomb threat from an unidentified male.
He told the dispatcher that two pipe bombs in a backpack at the school were going to detonate Tuesday morning.
A bomb squad with the Riverside County Sheriff's Department searched the campus using K-9 support. By 6 a.m., investigators determined they weren't going to be able to clear the campus in time.
That's when automated emails and text messages were sent out to all parents about a suspicious object on campus, and that a decision was made to cancel school for the day with the safety of students and staff in mind.
During the search, a dog alerted investigators to a locker with a backpack, but nothing was found. According to the assistant superintendent, that backpack was left behind by a student as a coincidence and had nothing to do with the threat.
By 8 a.m., the campus was rendered safe after the threat was determined to be a hoax. Classes remained canceled but school officials said extra-curricular activities will go ahead as scheduled.
The incident was under investigation by Corona police.