A 29-year-old man was arrested Sunday on suspicion of involvement in the death of his girlfriend's two young daughters in their apartment, police said.
They said Atsushi Inami was arrested when he was spotted with cardboard boxes containing the girls' bodies in Chuo Ward at around 5 a.m.
The girls were identified as Seina Konno, 4, and her sister Hina, 3, the daughters of Nozomi Konno, 24, who has lived with Inami since summer, the police said.
The corpses had bruises on their faces and bodies, the police said. Inami allegedly told police he assaulted the girls when trying to teach them how to behave.
According to investigations, Inami allegedly put the younger girl's body in a cardboard box and hid it in a closet around Sept. 8 and the older girl's body in a box last Thursday.
Apparently after finding the boxes, the mother alerted a neighbor at around 8 p.m. Saturday, who called the police.