"We have arrested Rapiush Ch Sangma, Deputy Chairman of GNLA, at his residence in Bangalore," Director General of Police (DGP) Peter James Pyngrope Hanaman told PTI.
Sangma was visiting the city with his wife and children frequently and he was there for about three months, he said.
Describing the arrest as a big catch, Hanaman said the arrest of Sangma, who is 'second-in-command' in the outfit, will have an impact on the GNLA organisational level strategy.
During the raid conducted early today, 20 SIM cards, a laptop, a tablet phone and nine mobile phones were recovered from his residence, police said.
Sangma was accused of being instrumental in planning all kidnappings, extortions and other anti social activities in Garo Hills region which were executed by the GNLA.