According to Nalgonda Superintendent of Police T Prabhakar Rao, a case was yesterday registered against accused R Harish following a complaint by the victims.
Harish, who was appointed by the NGO management was also staying in the same hostel in Enemeedha Tanda under Tungaturthy Gram Panchayat, where the abuse happened. He allegedly threatened the girls and sexually abused them, a police official said.
As many as 78 students comprising boys and girls are staying in the hostel.
However, sources in the department said that police have already nabbed Harish and are questioning him.
The couple -- Srinivas and Sarita-- who are running the NGO will also be questioned on any violations in running the hostel, the police official said.
As of now, a case under relevant sections of protection of children from sexual assault besides cheating, has been registered, he added.