The female rhinoceros had strayed last night from the flood-hit park around 7:00 pm and a search operation was launched, Divisional Forest Officer Dibyodhar Gogoi told PTI.
Gun shots were heard early this morning and a search of the east division of the Karbi Anglong hills found the pachyderm in a seriously injured state, Gogoi said.
The poachers took away the horn after sawing it off and a part of the right ear and veterinarians were trying to save the rhinoceros, he said.
The carcass of another rhinoceros was recovered during the day from the Bagori range of the park with its horn sawed off, park sources said.
KNP Director Sanjib Kumar Bora said anti-poaching camp personnel were on high alert in the park.
The attack on the rhinoceroses led to blockade of the National Highway 37 passing beside of KNP, by local people, All Assam Students Union and Asom Jatiyatabadi Yuba Chatra Parishad.
The demonstrators burnt the effigies of Chief Minister Tarun Gogoi and Forest minister Rockybul Hussain alleging that they had failed to protect the animals in the park.
The demonstrators also suspected the poachers to be Bangladeshi migrants and alleged that the government had failed to evict them.
