An accused and his relatives also attacked the boy's family when they were going to report the incident to the police, they said. One of the accused, Vikram, has been arrested, police said.
"The assault took place on May 27 when the boy had gone to a shop. One of the accused lured him on the pretext of showing pigeon. Eight men then sodomised the boy at the residence of one of them and videographed the crime," said a police official.
They then threatened the boy that they would kill his parents if he revealed the incident to anyone.
"The boy did not tell anyone about the incident. However, his elder brother saw some of the accused making fun of him. He informed his parents about it, after which the victim revealed his ordeal to his parents," the official said.
When the family was on their way to the police station to report the incident, the boy saw one of the accused standing at a shop and pointed toward him. When the boy's father confronted him, the accused along with his relatives attacked the victim's family.
A PCR van reached the spot following which the attackers fled the spot. The injured were rushed to hospital and discharged after treatment.
The victim's family has identified the accused as Jeevan, Dilip, Manish, Khemu, Monu, Devi, Panchi and Vikram who live close to their house, police said.
A medical examination of the boy has confirmed the assault. Police have got him counselled by an NGO and he has also been given medical aid.
"We have registered two case, one under IPC Section 377 (unnatural offence) and Prevention of Child from Sexual Offences (POCSO) and another for the attack on the victim's family, at Geeta Colony Police station," said Deputy Commissioner of Police (East) Ajay Kumar.