Rajendra Meena (42) was a labourer and staying in a house constructed in the farm in Kankaria area, they said.
He, along with his wife Nirmo Devi (38) and two sons, Ramavtar (20) and Asharam (15), was sleeping on the terrace of their house last night and all of them were found dead, SHO Sapotara police station Amar Singh said.
Prima facie, they died due to poison consumption, the SHO said.
Food poisoning could be a reason or they might have also committed suicide, he said, adding the matter is being probed to ascertain the facts.