A local villager has been taken into custody in connection with the incident under Balodabazar forest division.
"The incident took place in the forest near Mohnda village managed by Forest Development Corporation and located just outside the sanctuary," Principal Chief Conservator of Forest (Wildlife) Ramprakash told PTI.
The incident came to light last evening, when some locals spotted the carcasses of the endangered species near a pond outside the village, about 90kms from the state capital.
They later informed the forest officials, he said.
He did not rule out poaching angle and said, "a suspect, a local villager, has been taken into custody and was being interrogated."
"Water and viscera samples of the dead deer have been sent to lab for testing which will further throw light on the case," he added.