The detained member had been involved with Allahr Din since 2001
Al Shahariya Rokan, 32, a regional nayek of Allahr Dal, was detained from Elisa Super Market in Sadar upazila on Tuesday.
Assistant Director and Media Officer of RAB 13 Khondker Golam Mortuza said: "After primary interrogation, Shahariya said he has been involved with the banned militant outfit since 2001.
"Shahariya used to extort money for the organization," Mortuza added. "He was attempting to reorganize by recruiting members."
Mortuza said a team of RAB 13 detained Shahariya acting on a tip-off. They are carrying on their operation to find Shahariya's associates.