Biswanath Sub divisional police officer Praneswar Doley told PTI that two of the poachers were trying to sell a rhino horn weighing about 1.10 kg to a customer for Rs 70 lakh.
The arrested poachers were identified as Pabitra Doley of Bokakhat, Sunil Maji, Rotiram Maji, Kharshing Terong and Biren Terong (all from Biswanath Chariali), Doley said.
According to police the horn was of a rhino in the Agaratoli Range of Kaziranga National Park near Bokakhat in Upper Assam.
Police has sent the horn to the state forensic laboratory in Guwahati.
