Following this, the Reserve's Deputy Director Kiran Bisen, veterinary doctor Akilesh Mishra and others reached the spot.The reason behind the tiger's death is yet to be ascertained and a postmortem will be conducted as per the guidelines of the National Tiger Conservation Authority (NTCA), he added.However, Sengar denied that the feline was poached, adding, prima facie, the tiger may have died a natural death.A large part of the carcass was in a bad shape, the officer added.