Militant kingpin Masukur Rahman alias Masud alias Ranbir who has been arrested in Rohingya camp area of Cox’s Bazar was a postal worker and infamous robber in his early life.
Ranbir was arrested several times in robbery cases and served time earlier, Rapid Action Battalion (RAB) said.
Ranbir is now the head of the military wing of new militant organisation 'Jamatul Ansar Fil Hindal Sharqiya'.
He got involved in extremism after he came in contact with top leaders of militant outfit Jamatul Mujahideen Bangladesh (JMB) in prison.
The elite-force RAB arrested 44-year-old Ranbir along with his accomplice Abul Bashar Mridha in Rohingya camp area at Kutupalong in Cox's Bazar on Monday. Bashar was a 'bomb expert' of the militant outfit.
Detailed information about militants Ranbir and Bashar were disclosed in a press conference at the RAB's media centre in Kawranbazar of the capital on Tuesday.
Addressing the press briefing, RAB's Law and Media Branch Director Commander Khandaker Al Moin said Ranbir is also a Shura member of Jamaatul Ansar. His home is located in Sylhet.
Ranbir was playing an 'important' role in the new militant group, the RAB director said.
"He used to select members of the military wing along with the invitation and training programmes of the militant organisation in Sylhet region.
From its inception, he was playing an important role in various policy-making matters of the military wing of the militant organisation.
"Under the guidance of the Ameer of the organisation, he organised meetings of several Shura Committees in different places of the country, including Padua Bazaar in Cumilla.
In these meetings, decisions were taken on various policy matters, including the activities of the military wing of the organisation."
In 2021, Jamaatul Ansar's 'training agreement' with separatist party KNF or Bomb Party, it was reported that Ranbir was present in the press conference along with the militant organisation's Amir and other Shura members.
A year ago, he took charge as the head of the military wing. After he took charge of the military wing, he assigned training in the hilly areas. “He went to Chattogram Hill Tracts for training at various times.
Besides, he went to various places, including Sylhet and Cumilla, and selected and appointed members of the military wing.
The RAB officer said Ranbir was involved in the disappearance of four youths from Sylhet in November 2021.
After various training, he joined the four missing youths in the military branch. Arms and ammunition were purchased for training under his guidance and supervision.
Ranbir was hiding in different parts of the country, including Sylhet and Cumilla, when the RAB started operation in the hills.
“A few days ago, he stayed in the area adjacent to the Rohingya camp in Cox's Bazar to hide himself."