The 22-year-old woman surnamed Kim was arrested on Feb. 11 after the corpse of the 3-year-old was discovered the previous day at her home in a multiunit house in Gumi, 260 kilometers southeast of Seoul. Kim was accused of abandoning the child, leading to her death, after she moved out of her home in August last year to remarry.

At first, the dead girl was believed to be Kim's daughter, but she was later found to be her younger sister.

Kim was sentenced to 20 years in jail by a district court in June but immediately lodged an appeal.

The Daegu High Court dismissed Kim's appeal, saying she deserves stern punishment for inflicting unimaginable pain on the dead child.

"Considering the need to sternly punish the defendant and isolate her from society for a long period of time, a lower court's sentence cannot be seen as too heavy or too light," the appellate court said. In the previous hearing held on Aug. 19, prosecutors demanded imprisonment of 25 years for Kim.

The case took a bizarre twist in early March, when it was discovered through DNA tests that Kim's 48-year-old mother surnamed Seok, who lived on a different floor of the same multiunit house, is the biological mother of the dead girl.

Prosecutors suspect that Kim and Seok each gave birth to baby girls between March and April 2018, and the elder woman may have switched the babies so her baby would be raised by her adult daughter. They have yet to discover the whereabouts of Kim's missing daughter, let alone whether she is alive or dead, in the face of stubborn denials by the two defendants.

Seok has also been indicted on charges of attempting to abandon the body of her 3-year-old daughter in February and abducting her granddaughter of the same age in 2018. Seok was sentenced to eight years in prison by a district court on Aug. 17. (Yonhap)