Abdullah Al Mamun, 32, who owned a travel agency, was taken away from his home in Bijoynagar area around 1.30 pm on Wednesday.
His brother Emdadul Haque Khokon filed a case with the police in this connection, Paltan Police Station OC Morshed Alam told bdnews24.com.
"Around 1.30 pm (on Wednesday), seven to eight men, identifying themselves as detective police, went to Mamun's office. They took him away in a black microbus (Dhaka Metro Cha 53-6754)," said 'Nasir', a friend of Haque.
The family rushed to the Dhaka Metropolitan Police's Detective Branch (DB) headquarters immediately after the incident.
They were told that the DB was not aware of any such arrest or detention.