The victim's family said they suspect the Class 9 student was raped and four local boys were involved in the incident.
But police are yet to establish the motive or their involvement in the crime.
According to officials, the victim had gone to sleep in the same room as two of her younger brothers on Monday night.
On Tuesday morning, however, her burnt body was found in the verandah outside the room. The room was latched from outside.
Till now, police have not been able to explain how the victim got outside the room without arousing suspicion.
Police sources said the victim suffered 100% burns and kerosene was used to commit the crime. They also suspect she may have been killed before being burnt.
Police officials said they are waiting for the postmortem report and a case of murder has been registered for the time being.