The militant also known as Birkhang Basumatary was directly involved in the killing of eight Adivasis at Lungsung on December 23 and six Hindi-speaking persons at Serfanguri in Kokrajhar district of Assam on January 16 last year, IGP L R Bishnoi told PTI.
Terming the arrest as a "big catch", Bishnoi said the arrest was made on a tip off by the Assam Police.
The NDFB(S) had launched an attack on adivasis in Sonitpur and Kokrajhar districts on December 23 last following which there was retaliatory violence and police firing resulting in the killing of 81 persons.