The National Office of Investigation(NOI) under the National Police Agency had opened investigations into 400 out of 420 submitted cases of newborns unregistered in the state system as of Tuesday afternoon.

The latest tally more than doubled from Monday’s, suggesting that the outcome of ongoing probes by the central and local governments may result in an exponential increase.

The NOI said 15 deaths have been confirmed, and the Gyeonggi Nambu Provincial Police Agency has opened criminal investigations into eight of the cases.

A mother in Suwon, Gyeonggi Province, has been referred to the prosecution for allegedly killing her two children after giving birth in 2018 and 2019 and hiding their bodies inside the refrigerator in the family home.

In the southeastern city of Busan, police began investigating a case involving parents who buried the body of their eight-day-old daughter after she allegedly died in their home.

The police are attempting to ascertain the whereabouts of 353 other children.