Two people who identified them as members of the Detective Branch (DB) were arrested for extorting people in Ranisankail upazila of Thakurgaon on Wednesday.
The detainees--Munna Hossain, 36, son of Yusuf Khalifa and Nur Mohammad, 37, son of Abdul Mannan, are residents of Phulbaria upazila in Dinajpur.
Gulfamul Islam Mandal, officer-in-charge of Ranisankail police station, said the detainees identifying them as the DB men realised Tk 18,000 from an indigenous Amin Mardic by intimidating him that he will be implicated in a drug case unless the money is paid.
The incident happened in Sundarpur area under Hossaingaon union of the upazila at noon, he said.
Suspecting their movement, locals informed police of the matter and caught them, the OC said.
During the primary interrogation, the detainees confessed to realising the extortion money from the man by issuing a threat to implicate in a drug case, he said.
A process was underway to file cases against them in this connection, the OC added.