The three sustained burns while in their sleep when a fire broke out at their house in Salna early August 17
Two more members of a family in Gazipur, who received burn injuries in a fire, have died at Dhaka Medical College and Hospital (DMCH).
Yakub Ali, 60, and his father-in-law Nur Mohammad Sheikh, 80, died at the burn unit on Monday afternoon, taking the death toll in the incident to three.
Earlier on August 17, Yakub's wife Aklima Bibi, 50, died while undergoing treatment at the hospital.
DMCH police outpost Inspector Bachchu Mia said Yakub died around 2:20pm, while Nur Mohammad died sometime later.
Quoting physicians, the police official said Yakub received 98% burns, Aklima 96%, and Nur 25%.
The three sustained burns while in their sleep when a fire broke out at their house in Salna early August 17, said Shahin, a cousin of Aklima.
The fire occurred from an explosion that might have been caused by gas leakage, and short circuit, he added.