Police detained Liton Sarkar after the death of his wife, Poppy Rani Sarkar, in Gomgram village of Dhamrai on 2 August.
Investigating officer Shahidul Islam said police recovered her body that night and sent it to Shaheed Suhrawardy Medical College Hospital for an autopsy.
Police initially found multiple injury marks on her body, Shahidul Islam said.
He said the cause of death could be confirmed only after the autopsy report is received.
Family members alleged that a domestic dispute led Liton Sarkar to beat Poppy Rani Sarkar with a stick.
They alleged that the assault occurred in front of the couple’s seven-year-old child and left her unconscious.
Family members said Liton Sarkar later took her to Kalamapur Holy General Hospital with help from local people.
She was declared dead at the hospital, and local people then handed Liton Sarkar to police.
Her father, Parimal Sarkar, alleged that his daughter had faced physical abuse since her marriage and that previous incidents had led him to take her to his home.
He alleged that the latest beating caused her death.
Police said they were processing the family’s complaint and taking legal action.