Lake Braddock Secondary School staff received a bomb threat via email, according to the school and Fairfax County Public schools representative John Torre.
Police were notified of the threat at 2 a.m. Monday morning and deployed K-9 units and other officers to search the school.
Classes were initially delayed two hours, but to give the teams more time to canvas the building, school was canceled for the remainder of the day.
The search teams found nothing to substantiate the threat and the building was deemed safe for occupancy by 10 a.m., Torre said. After school and evening activities were scheduled to proceed as normal.