A broken rear window on a 2001 Mazda Tribute. On the morning of Wednesday, Sept. 18, 2013, a teacher walking through the parking lot of Aloha High School in Beaverton, Ore., heard a "loud pop" and then saw a broken window on this SUV. He assumed that the vehicle had been shot out, which prompted a school lock down. Investigators later determined that the window had shattered accidentally. (Washington County Sheriff's Office)

Aloha HS placed on lockdown

A teacher mistook a what appears to have been an SUV’s shattering window for a gunshot.