Kaziranga National Park authorities arrested seven poachers during an operation at Bokakhat on Friday night.
Forest officials recovered a huge quantity of tiger skin, bones, nails and teeth of Royal Bengal tigers in a Tata Magic on National Highway 37.
Divisional forest officer Rohini Ballav Saikia said the items were meant for sale.
The poachers, identified as Balbir Singh alias Bablu, 27, from Golaghat district, Dharansingh Bey, 24, Babu Teron alias Daysing Teron, 22, Barelong Teron, 23, Dilip Teron, 30, Jaysing Bey, 27, and Manjit Singh alias Biki, are from Karbi Anglong district .
Sources said the tiger was killed in the dense forests of Karbi Anglong.
Saikia said more details would be available after interrogation.
A case have been registered under the Wildlife Protection Act in Bokakhat police station.
In July last year, forest officials had arrested six persons involved in poaching of a Royal Bengal tiger in Manas which is also a tiger reserve.