Stonington — Ten police dog teams spent 30 minutes Tuesday morning conducting a drug sweep of Stonington High School.

The K-9 teams, which walked through hallways with lockers and the parking lots while students and staff remained in their classrooms, did not detect any illegal drugs.

Teams from the Stonington, Waterford, Westerly, Groton Town, Norwich and Montville police departments, along with state police, all participated in the sweep, which began about 8:30 a.m.

Since 2014, police, in cooperation with the high school administration, periodically have conducted sweeps of the school with area K-9 teams. Past sweeps have resulted in a few instances of marijuana being discovered in cars and lockers.