Rapid Action Battalion (Rab) arrested a member of Jamaat-ul-Mujahideen Bangladesh from Chapal area under Godagari upazila of Rajshahi on Saturday night.
The arrestee was identified as Torikul Islam, 40, son of late Lokmanul Haque Biswas, hailing from Kadikola village under Nachol upazila in Capainawabganj.
RAB disclosed the matter in a press conference on Sunday.
The members of RAB-5 also seized extremist leaflets from his possession.
A criminal case was filed against him with Kotwali police station.