Jasim Uddin, a local trader, filed the case with the court of Metropolitan Magistrate Abu Salem Mohammad Noman.
The court directed the Deputy Commissioner of Detective Branch (DB) to investigate the matter.
The other accused are sub-inspector Nazrul of Satkania Police Station, Sub-inspector Hannan of Daudkandi Police Station, Ziaur Rahman, Bishnupad Palit, Kajal Kanti Baidya, and AM Sahabuddin.
The case statement said Liaqat called Jashim at DB office on June 14, 2014 for interrogation, demanded Tk 5 lakh and threatened to kill him in crossfire if he fails to provide the money.
Later, Jashim was made accused in a case filed over theft as he managed to pay only Tk 2,50,000.
Also read: Major (retd) Sinha murder: Accused put on further 4 days of remand