The leopard named 'Linkan' was the only big cat and a major attraction for visitors to the park in Brook's Hill, located inside the city.
Though other animals including deer and bear inhabit the park, which is also a wildlife rehabilitation centre, tourists were always seen thronging to cage number 1, the enclosure of Linkan, divisional forest officer, wildlife, Sambalpur division, S Nayak said.
The leopard had been rescued from Rairakhol forests in the district when it was only two months old and then became the only tiger in the centre ever since, he said.
Two vets from the Odisha University of Agriculture and Technology (OUAT) at Bhubaneswar were looking after Linkan for two days.
A post-mortem was conducted and the carcass was consigned to flame inside the park, the sources said.
Meanwhile, the regional chief conservator of forests (RCCF), Sambalpur, said he would urge the state government to provide another tiger to the park.