The rhino was killed yesterday near Hatibandi Camp under Bagori range on the southern side of the park along Nagaon and Karbi Anglong districts, divisional forest officer (DFO) D D Gogoi said today.
Two empty cartridges of AK-47 assault rifle were recovered near the carcass, Gogoi said.
The police suspect the involvement of Karbi Peoples Liberation Tiger (KPLT) insurgents in the poaching.
A male rhino was killed on Sunday night near Borholla camp in the Burapahar range of the park.