Police detained Anwar Hossain, also known as Titu, after an alleged armed extortion attempt at a rented flat in Maijdee, Noakhali.
Police alleged that three people entered the fourth-floor flat in Hock Mansion and demanded Tk1 million.
Police said the group used a pistol to threaten the occupants and forced a signature on a blank stamp paper.
The affected family also alleged that the group took Tk27,000 from the flat.
Police said they surrounded the building after receiving information about the incident.
Titu was detained while attempting to leave by the stairway, police said, while two others escaped.
Police said they recovered a foreign-made pistol, five rounds of ammunition, 40 yaba tablets, Tk27,000 and two mobile phones from him.
Police also said they seized two motorcycles from outside the building.
Police said Titu had seven previous cases registered at Begumganj police station, though the two accounts list the alleged offences differently.
The reported status and type of new cases differ: one police account said arms and extortion cases would be filed, while another said arms and narcotics cases had been filed.
Police said efforts were continuing to locate the two people who escaped.