Tran Van Khoi, 26, had shared a house with a 23-year-old woman and her daughter in August, police said Saturday.
According to police, Khoi often beat the girl, burned her with cigarettes, and pulled her teeth.
On Nov. 18, after the girl had fouled her pants, Khoi beat her until she lost consciousness. He and the girl's mother then took her to hospital but she was declared dead on arrival. After burying her body, the couple ran away.
Medics were concerned over the girl's cause of death and contacted police. Khoi was arrested while hiding at a local apartment.
The mother is still unaccounted for.