Patna: A Class X student was allegedly blackmailed and gang-raped by 15 students, two teachers and the principal of a private school in Saran district's Ekma since December last year.

Her father was away from home for the last six months, and the girl could not muster courage to approach the police. On Friday, when he returned, the girl narrated her woes to him. He went to the school to inquire. When he left the school, the principal, teachers and some students allegedly thrashed the girl.

She somehow managed to escape and reached the Ekma police station, around 60km north of Patna.

She narrated her ordeal to station house officer (SHO) Anuj Kumar Singh, who told his counterpart at the Woman police station in Chhapra to record the survivor's statement and initiated investigation.

The girl told the interrogators that five students had first raped her in the school toilet in December. The principal's son also allegedly joined the group that used to sexually exploit her. When she complained to the principal, he allegedly told her not to lodge any police complaint saying it would bring dishonour to her family. Then, he also raped her.

Saran superintendent of police (SP) Har Kishore Rai said the girl was sent for medical examination and a case was registered against 18 persons. A police team later arrested the principal, Uday Kumar Singh alias Mukund Singh, a teacher named Balaji, and two students.

"Raids are underway to nab the other accused in the case. The medical report is awaited," the SP said, adding that the girl was being counselled by doctors and women police officials. "The case needs to be handled carefully," the SP told The Telegraph over phone.

The SP said a special investigation team headed by deputy superintendent of police Ajay Kumar Singh has been set up to investigate the case.

"No guilty persons will be spared, whosoever they may be," he asserted.

As the news spread, a group of residents tried to ransack the school but the police stopped them.

Woman police SHO Indra Rani said the survivor would be produced before a judicial magistrate on Saturday to record her statement.