Lucknow, Sep 18: A girl student of Class IX, studying in a private school in Deoria district of Uttar Pradesh, died on Monday after falling off the third storey of the building on Monday, police said. Deceased Neetu Chauhan, 16, was found lying on the ground of the Modern City Montessori School in a critical condition. She had gone to toilet, located on the third floor, and her classroom was on the first floor, students said. A profusely bleeding girl was rushed to a nearby medical facility from where she was referred to Baba Raghav Das Medical College in Gorakhpur, but she succumbed on the way, Senior Superintendent of Police (SSP) Rajiv Malhotra told IANS. Parents of the girl have lodged a police complaint against unknown persons, alleging that she was thrown off the third floor. After autopsy, the body has been handed over to the family, Malhotra said. Apprehending trouble from the parents of other students, the school management has locked down the school and gone untraceable. Police said the mobile phone of school's Principal Adya Tiwari was switched off since the incident. The SSP said the matter had been referred to the District Magistrate and he in turn had deputed the District Inspector of Schools (DIOs) to probe the incident. An FIR, the police official said, would be lodged on Tuesday and a probe initiated.