The deceased was identified as Asma Begum, 32, wife of Ismail Hossain Babul of Kalardap in Noakhali Sadar upazila.
Five people, including Asma and her stepson, suffered burns when a fire broke out at their house on Monday.
Four others victims are -- Kamal Uddin, 35, son of Babul, Manna, 22, son of Ruhul Amin, Sumon, 30, son of Abdus Shahid of the village and Tarek Hossain, 22, son of Abul Hossain of Shibpur village in the upazila.
Tomas Barua, officer-in-charge of Sudharam Model Police Station, said a fire broke out at Babul’s house in the morning in which five people were injured.
Three of them were sent to the burn unit of Dhaka Medical College Hospital for better treatment. Asma, who suffered 90 percent burns, succumbed to her injuries there, police said.
Of the injured, Kamal sustained 30 percent burns while Tarek suffered 15 percent burn injuries.
Locals said Asma and her stepson Kamal were at loggerheads over the ownership of a piece of land.
Police said they suspect Asma might have set the house on fire.
Police detained Kamal’s brother-in-law Shamim Hossain, 19, for questioning.
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