The militants lobbed the explosive at the house of M Sara (55) at Uchekon area, 15 km from here last evening.
Sarat and his family members were present at the time of the incident.
Sarat's wife Sorojini Devi is contesting the panchayat elections for the post of pradhan and unidentified miscreants had earlier threatened her with dire consequences if she contested the elections.
It was not immediately known whether the hurling of grenade was connected with the proposed candidature of Sorojini for Pradhan or monetary demand from the contractor, the sources said.
