Three parents contacted police following the Oct. 1 incident at the school, about 35 miles southwest of Detroit.
"They wanted to report a strip-search of seventh-grade girls," Deputy Chief Thomas Moore said Wednesday. "We're not talking about nude, but stripped down to their undergarments."
Police have interviewed the three girls who said they were ordered to disrobe. Investigators will turn over their information to the county prosecutor, possibly by the end of the week.
The school has 176 students from preschool through eighth grade. Names of the teacher and principal were not released, AuBuchon said.
The teacher has not been put on leave and is still teaching, AuBuchon said.
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