Students at Hopkinton High School were dismissed early Thursday after a single round of ammunition was found inside of the school.
In an e-mail sent to parents, principal Evan Bishop wrote that the ammunition was found inside of the boys team room on Thursday morning.
The school immediately called both fire and police departments to the scene.
After a thorough search of the building, Hopkinton police say that there were no weapons or other ammunition found at the school. They say that there is no reason to believe that a weapon was brought on the school grounds.
Massachusetts State Police, environmental police, and Worcester police assisted in the search of the building.