The investigation into the case gained traction as her 36-year-old father, who was put under emergency arrest, confessed Thursday to having dumped her body on a hill in the city 270 kilometers south of Seoul in April.

Based on the father's statement, police presume that Koh died because she choked on food. Her father has said that he concealed her death for fear that it would cause trouble in his divorce settlement with her birth mother.

Police plan to examine her body to find out the exact cause of death, officials said.

Police opened their investigation into Koh's case after her stepmother reported to the police on Dec. 8 that she had gone missing.

They mobilized 3,000 personnel, search dogs and helicopters to find her over the past few weeks. (Yonhap)