A 12-year-old student in camouflage gear was arrested Friday for bringing two rifles and a shotgun to his school, police said.

No shots were fired and no one was hurt, but about 1,100 students were evacuated from Bull Run Middle School (search), about 35 miles west of Washington.

Police also arrested a woman who works in the school cafeteria and knew about the guns, but kept silent. Naomi Lewis, 38, gave the boy a ride to school and kept the guns locked in her car, Chief Charlie T. Deane told The Washington Post.

An assistant principal making his morning rounds found the armed boy in a bathroom, Prince William County police said.

"The assistant principal's very tall, and he looked over the stall and he observed ... a weapon," said Chief Charlie T. Deane. "Subsequently, other weapons were found in that general area."

The assistant principal left the bathroom, called police, and began the evacuation. Officers arrived and arrested the boy, who was dressed in full camouflage gear (search), Deane said.

"There's some information that he may have been trying to frighten people who had been picking on him, or something," Deane said.

WJLA-TV showed video of a police raid on the arrested school employee's home in nearby Haymarket, Va., where investigators carted off several computers.

As many as 10 other students were questioned about the guns, police said.

Friday was supposed to be the last day of the school year at Bull Run. The school planned to open Saturday and Monday so students could pick up their belongings. Counselors also would be available.

"It's just absolutely shocking. The first thing that goes through your mind is please God, don't let it be my child, because we thought someone was injured," said parent Jane Luke.