Rapid Action Battalion (RAB) spokesmen said they had arrested Touhidur Rahman, 58, and two other "active members" of Ansarullah Bangla Team, which was banned in May over a spate of killings of bloggers.
"We've arrested them in the capital today. We can confirm that Rahman is a Bangladesh origin British citizen. He is the main planner of the attacks on Avijit Roy and Ananta Bijoy Das," Major Maksudul Alam of the RAB told AFP.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.