STILLWATER, Okla. – A 13-year-old student shot and killed himself in a hallway at an Oklahoma junior high school before classes began Wednesday, police said, terrifying teenagers who feared a gunman was on the loose.

Staffers quickly locked down the school and evacuated about 700 eighth and ninth graders, along with students from an adjacent elementary school, to a safe location, police Capt. Randy Dickerson said. The eighth grader was found dead in a hallway, Dickerson said.

Some students who fled the building said they found out it was a suicide from news reports. Other students who had witnessed the shooting spread word that a classmate had killed himself, police said.