A 31-year-old woman whose husband was arrested last month on suspicion of assaulting their 10-year-old daughter just before the girl's death was detained by police Monday for allegedly failing to stop the attack, investigative sources said.
Nagisa Kurihara is suspected of failing to stop the assault on Jan. 24, which allegedly included dousing their daughter, Mia, with cold water from the shower.
Yuichiro Kurihara, 41, was arrested on Jan. 25, after his daughter was found dead with bruises in the bathroom of the family's house in the city of Noda, Chiba Prefecture, the previous night.