Fatuha: A threat to expose the misdeeds of the arrested girl student of a residential public school in Fatuha proved fatal for six-year-old Abhimanyu, who was strangulated to death in his hostel room late on Sunday night, police said on Friday.

The special investigation team headed by Fatuha sub-divisional police officer Sunil Kumar has stumbled upon evidence which suggest that Abhimanyu had threatened the Class VIII girl student with disclosing her "intimate relationship" with a watchman of Sephali International Residential School.

An investigating officer revealed that the girl student (suspected to be the main accused), who is in custody, slapped Abhimanyu - when the boy had threatened her on July 8 - the night he was strangulated to death - that he would expose her misdeeds. "The girl was already irritated with the boy for his behaviour. The boy often tore her answer books and other study materials," the officer said.

Police sources said that during her 72-hour interrogation, the 16-year-old girl admitted that she decided to kill Abhimanyu, a student of Lower KG - as she feared that her "cordial relations" with the watchman would be made public. " Samaj mein pariwar ki badnami hoti. Isliye maine Abhimanyu ko mar diya (I killed Abhimanyu because it would have earned disrepute to the family in the society)," a police officer quoted the girl as saying.

The girl, a resident of Vaishali district, reportedly confessed to the crime and disclosed that she strangulated the child to death while he was asleep. Though the boy resisted a bit, she silenced him by putting extreme pressure around his neck for 10-15 minutes. "The post mortem report has corroborated the girl's statement," said Patna superintendent of police (rural) Anand Kumar.

He said that the girl in her two-and-a-half-minute statement, which was video-recorded, revealed how she had killed Abhimanyu in the hostel room. She disclosed that the child had spotted her and the watchman in the toilet of the hostel on July 6, two days before the murder. On July 7, Pappu again tried to take her to the toilet but couldn't do so as some girls were present, Anand said.

The Class VIII student, who was taken into custody and subsequently produced before the juvenile justice board on Thursday after questioning, was sent for medical examination on Friday. "The medical report is awaited. The report will throw more light on her sexual relationship, if any," Anand told The Telegraph.

The police conducted raids at different hideouts on Friday to nab the watchman who is missing. Preliminary investigation revealed that the guard used to blackmail girls after making video clips of their "objectionable postures".

The school has two hostels - one on the school premises and another rented facility adjacent to the school building. The arrested girl and Abhimanyu stayed in the rented building.

Anand said the school has been closed following the murder.