Tokyo's Metropolitan Police Department sent Kenichi Hosoya and his wife, Shiho Hosoya, to prosecutors on Friday after their arrest Wednesday for allegedly killing their 4-year-old daughter, Yoshiki, by administering psychotropic drugs and antifreeze.

Yoshiki had been placed in a total of six child care facilities over a period of around three-and-a-half years starting after she was a couple of months old, according to Tokyo’s child consultation center and other sources. The MPD believe Yoshiki had been neglected, and are investigating the possibility that the suspects changed facilities frequently, fearing that the abuse would be discovered.

"To prevent such tragic cases from being repeated, it is important to fully grasp the facts of the case, including the family's upbringing and the responses of institutions involved," Ayuko Kato, minister in charge of children's policy, said Friday. "We will closely monitor the metropolitan government's inspection and the central government will also consider how to best respond.”