MONTERREY, Mexico (AP) - Municipal police say a 7-year-old was locked inside a classroom by his teacher as punishment for supposed misbehavior and left alone for six hours until he was rescued by officers around midnight.

The boy was found under the teacher's desk, covering himself with one of her sweaters for warmth.

Police say the boy's family started looking for him Monday after he didn't return home from school on time. One of the boy's friends said he had been punished by the teacher, so police were eventually called to the school and found the boy.

Education officials say the mother has filed a criminal complaint, and the case is under investigation.

The mother tells MVS Radio that the teacher had abused her son at least once before, by taping him to the legs of a desk.