Additional Superintendent of Police Satyendra Kumar said the victim's family has alleged that the minor was raped by a youth inside the school yesterday.
According to the girl's family, the school management denied any such incident when they tried to lodge the complaint with it, the ASP said.
He said that a case was lodged in the matter late last night and the school has been sealed this afternoon.
A large number of people reached the school this morning and indulged into brick batting after which police chased them, the ASP said.
The matter is being investigated, the ASP said.