"The police arrested NDFB-S insurgent Dipen Narzary alias Babailang alias Pahe from Kahugaon along with a 7.65 mm pistol with two rounds of ammunition and a grenade," IGP L R Bishnoi said.
Narzary had led the arson and burning of houses following the December violence, Bishnoi said.
Nearly 80 Adivasis were massacred by National Democratic Front of Bodoland-S extremists in Kokrajhar, Chirang and Sonitpur districts.