A man and his daughter have been found dead at Mohammadnagar under Labanchara police station in Khulna.
Police recovered the bodies of Parvin Sultana, 25, cashier of Exim Bank's Khulna branch, and her father Ilias Hossain, 75, from the septic tank of their residence around 12:30am Saturday.
Assistant Police Commissioner in Khulna Zia Uddin Ahmed said police are assuming that the duo were suffocated to death.
Parvin's brother Rezaul Islam said robbers killed his father and sister and then dumped their bodies into the septic tank.
Labanchara police station OC Sardar Mosharraf Hossain said no injury marks were found on the bodies.
He said: "Furniture and other valuables of the house were found in scattered condition. We will investigate to know the reason of the deaths."
The bodies were sent to Khulna Medical College Hospital morgue for autopsy.
