The workers were constructing a toilet at a school next to the temple in Faridpur’s Madhukhali Upazila
RAB spokesman Mufti Mahmud Khan told bdnews24.com that the three -- Touhidur Rahman, Sadek Ali and Aminul Mallick -- were picked up from Nilkhet and Dhanmondi areas of Dhaka.
One of them, Touhidur Rahman,was a fund raiser, he said, while the two others were activists.
Khan said the three were suspected of masterminding the murders of secular bloggers Avijit Roy and Ananta Bijoy Das.
Details will be provided later in a media conference, he said.
Meanwhile, The Guardian claimed in a report quoting RAB officials that Rahman was a British citizen.