Police recovered the bodies of a mother and her daughter from a room in a coaching centre at Muslimbagh, Keraniganj, on Thursday.
The deceased were identified as Rokeya Negem, 32, and her 14-year-old daughter Fatema, an eighth-grade student.
Keraniganj Model Police Station Officer-in-Charge M. Saiful Alam said locals alerted the police to a foul odor coming from the premises. Officers arrived at the scene around 10pm and found the bodies.
It is suspected that the killings occurred two to three days earlier. Four individuals have been detained for questioning, he added.
Residents said the coaching centre operated on the second floor of the building, and Fatema attended private tutoring there with her mother.
The motive for the double murder remains unknown.
The police have sent the bodies to Mitford Hospital morgue after completing the postmortem reports. A case has been filed at Keraniganj Model Police Station.