Updated

Authorities say a San Diego middle school was evacuated when a student's science project was mistaken for a bomb.

A Fire-Rescue spokesman says a concerned vice principal prompted the evacuation of Millennial Tech Magnet Middle School yesterday afternoon.

He says an arson team took photos and X-rays of the empty plastic bottle with wires and determined it was harmless.

He says the 11-year-old was trying to build a motion detector with instructions he found on the Internet and parts he bought online. His parents helped him buy the parts. They say they didn't realize the experiment looked threatening.