Police have recovered the bodies of a woman and her daughter from a flat at Merul Badda area of the capital.
The deceased were identified as Mahmuda Akhter Brishti, 33 and daughter Sanja Marwa, 10.
Police arrested Mahmuda's husband Selim, 40, for interrogation.
Md Sadek, sub-inspector of Badda police station, confirmed the matter.
The victims were first taken to Forazi Hospital in Banasree around 3am on Wednesday. As their condition was critical, they were referred to Dhaka Medical College Hospital (DMCH) where doctors declared the duo dead around 5:30am.
The detained Selim claimed that mother, daughter committed suicide taking poison.
However, doctors did not find any evidence of taking poison.
Police primarily suspected that they were strangled to death.
The bodies were kept at DMCH morgue for autopsies, said the police official.