Senior officials, including Director Chandrakant Patil, reached the spot and took the carcass into custody.

There were no visible injury marks on the big cat, Negi added.

A post-mortem examination was ordered and according to new norms by the National Tiger Conservation Authority, a panel of experts was required to be present when it was carried out.

Government veterinarian J.P. Tripathi, who carried out the process, said the death of the tigress seems to have been caused by poisoning because there were no signs of injury on the body.

He said the viscera would be sent for tests to the forensic science laboratory in Sagar and veterinary college, Jabalpur, for histopathology reports to confirm the cause of the tigress's death.