As per preliminary investigation, the minor girl got pregnant after she was allegedly raped last year by a 23-year-old youth, Anil, from her native Salgaon Khurd village, Koriya Superintendent of Police B S Dhruv told PTI.
After the girl delivered the baby at the pre-metric hostel in Ramgarh block of Koriya on January 2, the hostel superintendent - Kiran Kispotta - allegedly strangulated the infant to death to cover up the matter, he said.
On getting information about the offence, the buried body of the newborn was exhumed near the river in the girl's native village, Dhruv said.
Six persons, including Anil, his and the minor girl's relatives, were arrested on Tuesday in this connection.
The hostel superintendent Kiran and her husband Phoolsai were still at large, he said adding that efforts were on to nab them.
Further probe was on in this connection, he added.