WESTBROOK – A 3-year-old child drowned Monday while participating in a swimming lesson in a 3-foot-deep pool at a child care center, police said.

The boy, Andrew Thurston, had been participating in a lesson with other 3- to 4-year-olds when he was discovered facedown in the water at 10:38 a.m., Police Chief Paul McCarthy said. The boy was pronounced dead at Maine Medical Center.

There were five to six children in the pool, and there was an instructor in the room, McCarthy said. It’s unclear whether the instructor was in the water, he said.

Day care staff performed CPR and the resuscitation efforts continued en route to the hospital, where the boy was pronounced dead at 11:15 a.m., the chief said. An autopsy will be performed by the state medical examiner’s office.

The Maine Department of Health and Human Services has a representative who will be working with police on the investigation, said spokesman John Martins. The state agency wants to know if day care center rules were followed, he said.