Officials said the MLA of the Bodoland Peoples Front, which is an ally of the ruling Congress in Assam, has been named in seven cases after witnesses complained that he was leading the rioting mob holding an AK-47 rifle.
Both the Assam government and the Centre have in principle took the decision to hand over the cases involving Brahma to CBI.
Sources said investigating agencies are soon likely to arrest some more people, including a few prominent persons, who were involved in the violence which has claimed over 80 lives.
Brahma, who represents Kokrajhar (West) constituency, was arrested from his Dotoma residence near Kokrajhar town yesterday.
The MLA was charged under IPC sections 120B (criminal conspiracy), 147 (rioting), 148 (rioting armed with deadly weapons, 149 (unlawful assembly), 436 (mischief by fire or explosive substance), 427 (causing damage), 379 (theft) and 506 (criminal intimidation).
BPF is the ruling party in Bodoland Territorial Autonomous District whose chief is Hagrama Mohilary.