The carcass was found yesterday evening along the Assam-Arunachal Pradesh border, Divisional Forest Officer Rajen Choudhury said.
The miscreants allegedly killed the wild elephant and chopped off its tusk, nail and tongue.
A team of Aranya Surakhya samiti personnel found the carcass and informed the forest office.
Choudhury said investigations are on and efforts are being made to nab the miscreants.
A team of doctor will conduct the postmortem, he added.