MIDDLEBURY, Conn. (WTNH) — Memorial Middle School was put into a shelter-in-place Friday morning after a staff member found a bullet in a hallway, according to an announcement from Principal Jennifer Murphy.

The bullet was found at about 11:40 a.m., according to a message to parents. Middlebury police responded to do a sweep of the building.

The bullet was a single, unspent 9mm round, according to Murphy. Firearm detection K-9s did not find any additional bullets or any guns in the building.

Students were dismissed when the search was finished.

“We would like to thank our students and staff for their adherence to our safety protocols as well as for their patience and flexibility,” Murphy wrote.

Anyone with information about the bullet is asked to reach out to the school.