Police allegedly picked up Islami Oikya Jote (IOJ) Chairman Abdul Latif Nezami from his residence in the capital and released after a while without giving any reason.
Contacted, the IOJ chief two to three policemen went to his home at Gopalbagh around 9:30am and asked him to go with them.
"They kept me in the lockup for an hour and freed me around 11:00am without any interrogation," he told The Daily Star this evening.
Over nine hours after his release, Khaleda Zia, chief of the BNP-led 19-party combine in which IOJ is a component, issued a press statement demanding immediate and unconditional release of Nezami.
Police meanwhile denied picking up the IOJ leader.
Mehedi Hasan, assistant deputy commissioner of Dhaka Metropolitan Police (DMP) at Wari, said he has no such information.