NAUGATUCK, Conn. (WTNH) – An active criminal investigation was underway Wednesday at Naugatuck High School after a student reported that they saw a firearm inside a backpack.

“As our community expects, incidents relating to weapons are responded to swiftly and with a significant deployment of police resources,” the Naugatuck Police Department said in a written announcement. “We thank school staff, students, and the community for their efforts for seeing this incident to its conclusion.”

The school was placed in lockdown, but police said there is no threat to the students. Residents are being asked to avoid the area.

Police and a firearms detection K-9 went through the school, and did not find a gun, according to officers. No one was injured or arrested.