"The hardcore NDFB cadre involved in several cases of kidnappings and extortions was killed in an encounter with the police at Boko in Kamrup (rural) district", Superintendent of Police Partha Sarathi Mahanta told PTI here.
One pistol had been seized from the slain ultra identified as Simul Boro.
In another incident in neighbouring Baksa district, NDFB cadre Ajay Biswar was arrested and a large quantity of arms and ammunition seized from him.
A nine mm pistol, one hand grenade, six rounds of ammunition, some magazines and cash were seized from him and his interrogation is on.