Torrington Middle School was locked down earlier Tuesday after a rifle shell casing was found on the floor of the cafeteria, according to Board of Education Chairman Ken Traub and Torrington police.
Police arrived at the school, located at 200 Middle School Drive, around 12:15 p.m. Traub said the school went into a "soft lockdown" while authorities investigated.
According to police, the casing had fallen from the pocket of a 12-year-old student, who brought three of them to school.
Police said no weapons were involved and no threats were made.
Authorities are investigating the incident.
No arrests have been made.