A forest department source stated that it was an adult male of about six to seven years old and may have died after consuming poisoned substance.
The carcass has been sent for conducting post-mortem at the District Veterinary Hospital in Jorhat.
A few teeth and nails were reported to be missing, the source said.
There are three reserve forests and a wildlife sanctuary near the Assam-Nagaland border under Mariani Range of the Jorhat Forest Division, with several tea gardens and a large number of villages located in the periphery of the forests.
Incidences of leopards straying in human inhabited areas from the forests under Mariani Range have been gradually increasing since the past 10 years resulting in conflict with the wild animals.
There have been several cases of leopards being killed or maimed after wild cats picking up and killing cattle of the villagers in the adjoining area.
The sources said that after receiving complaints of leopards straying in human settlements, the forest department usually sets up cages to catch the leopards.
“But this does not provide a solution as the animal is let off in another forested area and may stray out and create havoc in the new area or be killed by another leopard in fight for supremacy of territory,” said sources.