A 16-year-old girl was allegedly gang-raped in a guesthouse at Gol Park by men aged 20 or less whom she had befriended on Instagram and later subdued into silence with the threat of posting a video of the crime on social media.

The school student was taken to the guesthouse in a last-minute change of plan, which was initially for lunch at Lake Mall where her mother had dropped her off.

Police said four youths — all college students — allegedly raped her one by one in two rooms of the guesthouse before she was dropped home.

Although the alleged incident happened in December, the video, which one of the assailants claimed to have shot, and the fear of social stigma had forced the family to remain silent till Monday, when they lodged a formal complaint at Rabindra Sarobar police station.

Kolkata Police arrested three of the accused on Monday night.

Deputy commissioner (south-east division) Bholanath Pandey said all the accused were college students and had been charged with sections of the Protection of Children from Sexual Offences (Pocso) Act.

According to the complaint lodged by the victim’s mother, the girl was added to an Instagram group without her consent, but she decided to stay on after seeing a few known persons.

“She got introduced to some members of the group through a common friend. On December 19, they planned a group lunch at Lake Mall. The girl’s mother dropped her at Lake Mall. One of her friends came to receive her. Her mother saw them take the elevator,” according to the complaint lodged by the mother.

However, she had no inkling that her daughter was convinced to exit the building almost immediately. An app cab was booked in which the girl and the others travelled while a few more young men rode a scooter,” said an officer associated with the probe.

The girl’s mother has complained that her daughter was repeatedly told to arrange for ₹2,500 to book the rooms at the guesthouse.

“The girl contacted her father, who was in the UK at the time. Busy in his work, he did not think much before making an online transfer to the account of a friend of his daughter who had UPI on his phone,” the complainant has mentioned.

The girl, the only minor in the group, wanted to leave when she saw that the youths were preparing to have alcohol. One of her friends, a girl who had come with another friend, left as she too felt uneasy, the victim’s mother reported.

“The victim, however, was not allowed to go and was raped by one of the college students. When the girl managed to reach the other room to inform the others about what had happened, one of the other youths told her he would do the same. Thereafter, the others too joined and gang-raped her, according to the complaint,” said a police investigator.

The girl reportedly locked herself in the washroom to save herself till the men started banging on the door, forcing her to come out. The youths allegedly threatened the girl not to report the matter, or else they would post on social media the video one of them had filmed.

“We are extremely thankful and happy that the police took serious cognisance of the offence,” said the family’s lawyer.

The accused were produced before the Alipore Pocso court on Tuesday and remanded in police custody till May 8.