Two staff members at an Illinois preschool have been placed on administrative leave after they were accused of making children stand naked as a form of punishment, the university that operated the program said Tuesday.

A 26-year-old Head Start teacher is said to have introduced the punishment in February at the program where she has worked for the last three years, according to the Southern Illinois University Edwardsville Police Department.

The university leases the classroom space from a community center in East St. Louis, about 30 minutes south of its main campus.

The teacher and a teacher's aide, who police said was aware of the punishments, lead a classroom of about 20 4- and 5-year-olds, according to SIUE police Chief Kevin Schmoll.

Students were allegedly asked to take off their clothes then stand in a closet naked as a way to discipline them. University police began investigating the accusations Thursday after a young boy told his parents about the supposed punishment, Schmoll said.

“That little boy is very brave for coming forward and telling us what was happening in his classroom,” Schmoll said.

Both the teacher and the 41-year-old teacher's aide have been placed on administrative leave while authorities investigate.

A letter has been sent to parents of other children in the class, and police will follow up with phone calls to determine if there are additional victims, Schmoll said. Interviews with children will begin in the first week of April.

Police are working with child services and prosecutors to determine whether the teachers will be charged with child abuse.