The girl was raped when she visited her older sister in the city of Magura last week. She was then treated for critical injuries, but died according to BBC on Thursday after suffering three heart stops.
I thought my daughter would survive. If she had made it, I would never have let her go anywhere alone again, says the mother to local media.
The older sister's 18-year-old husband, as well as his parents and brother, have been arrested.
Thousands of people attended a funeral prayer for the girl on Thursday. A large protest march was also held in the capital Dhaka.
The demonstrators are demanding justice for rape victims and strengthened legislation for crimes against women and children. They are also calling for clearer legal definitions of rape, reports BBC.
Bangladesh, like its neighboring country India, is plagued by extremely high levels of violence against women and children. Only days after the rape in Magura, at least three rapes of children were reported in the country.
