Park officials said they came upon the animal's carcass Monday along with a .303 rifle and live ammunition nearby.
"The poachers had shot the rhino ... [2,296 feet] from the Erasuti anti-poaching camp. The poachers probably shot at the rhino using a silencer as the guards did not hear any gun shot," said park Director N.K. Vasu.
Officials in Assam state, which includes Kaziranga, recently organized the Assam Forest Protection Force, armed with sophisticated weapons to deal with poachers, the Indo-Asian News Service reported.
Rhinoceros are killed and their horns taken. The horns are believed to have medicinal proprieties.