Police recovered the decomposed bodies of three members of the same family from their home in West Chanderkhola village of Raripara Union, Kachua, Bagerhat, on Tuesday afternoon.
The deceased were named as Ahad Hawlader, Monira Begum and Rashida Begum.
Ahad was identified as Monira Begum’s son, while Rashida Begum was identified as his grandmother.
Ahad’s age was stated as 22 in one account and 28 in another.
Neighbour Bulu Begum said a foul smell from the house prompted residents to look inside and notify police.
Kachua police officer-in-charge Harun Ar Rashid said officers found injury marks on the victims’ heads.
Harun Ar Rashid said police initially suspected homicide.
He said the deaths may have occurred two to three days before the bodies were found.
The officer said limited movement to and from the house meant the incident was not noticed earlier.
Police said the bodies were being sent for post-mortem examinations to determine the cause of death.
An investigation has been opened, and the circumstances of the deaths have not yet been established.