Divisional forest officer of Daying Ering wildlife division in Pasighat, Tashi Mize said the carcass of the buffalo was found yesterday from a marshy pond where wild animals come to drink water.
The carcass was found to be at least a week old and most of the animal's flesh was found chopped off.
Mize, who rushed to the spot on receiving information, said the length of the buffalo's horn was more than 3 feet and she might have been the largest one in the sanctuary.
DEWFEDS general secretary Oki Modi alleged that there were other incidents of poaching of deer and sambar recently in the sanctuary and its team during a visit to the sanctuary on June 8 and June 9 came across several huts of hunters and fishermen.
The forest department staff, he alleged, were neglecting their duties and go to the forest about once in a fortnight or when an officer visits.