"Carcass of the 12-year-old tigress was found yesterday. Her two cubs, 8-months old, were found dead today," field director of the Reserve Subhranjan Sen said.
Autopsy suggested that they had died of poisoning, but to confirm, viscera samples wold be sent to a laboratory, he told PTI.
"The tigress had four cubs. Two are dead. We have spotted another one (alive) but the fourth one is still to be traced," Sen said.
"We have launched probe to find the culprits who (possibly) poisoned them," he said, adding that patrolling in the area had been increased.