Touhidur Rahman, 58, and two active members of outlawed Islamist group Ansarullah Bangla Team were arrested in Dhaka on Monday night, said Maksudul Alam, a spokesman for the Rapid Action Battalion (RAB) force.
“Rahman is a Bangladeshi origin British citizen and we suspect he is the main planner of the killings of U.S. blogger Avijit Roy and Ananta Bijoy Das,” he told Reuters.
In February, machete-wielding assailants killed a U.S. citizen of Bangladeshi origin and critic of religious militancy, Avijit Roy, and seriously injured his wife and fellow blogger, Rafida Bonya Ahmed.
Another secular blogger, Ananta Bijoy Das, was hacked to death on May 12.
Militants have targeted secularist writers in Bangladesh in recent years, while the government has tried to crack down on hardline Islamist groups seeking to make the South Asian nation of 160 million people a sharia-based state.
Last week, police arrested two members of Ansarullah Bangla Team for alleged involvement in the killing of blogger Niloy Chatterjee on Aug. 7, the fourth such killing of an online critic of religious extremism in less than six months, spurring calls by human rights groups for a swift and thorough investigation.
On March 30, Washiqur Rahman, another secular blogger who aired his outrage over Roy’s death on social media, was killed in a similar fashion.