Bodies of Mahavir (46), his wife Chunni (43) and two minor sons Rajkumar and Pawan Kumar were found in their house, DIG Gyaneshwar Tiwari said.
The matter prima facie appears to be that of old enmity and probe in on in the matter.
The bodies have been sent for postmortem.
The six-year-old daughter and a son of Mahavir were saved as they were sleeping in a neighbour's house.