Naugatuck High School was locked down on Thursday morning as police conduct a pre-arranged drug sweep.
They searched lockers and parked cars and did not find narcotics, police said.
The sweep ended at 10:41 a.m.
Police said the sweep was not in response to any known problem or condition at the high school, but is a tool to ensure that the students have a safe and drug-free environment in which to learn.
