According police officials, the DHNA cadre was thrashed last night in the remote Tongibira village under Maibang police station.
The villagers were celebrating Busu Dima festival in the Tongibira village under Maibang police station when four DHNA cadres came and created some disturbances.
After this, villagers started beating the cadres, leading to death of one militant on the spot and two others were injured seriously.
The fourth one manged to escape from the scene, police said.
The cadre killed in the incident has been identified as Baite, while the injured ones are K Haflongbar and Debjoy.
The absconding cadre was identified as M Langthasa, police said.