What happened
Koh Yu-jeong and her former husband, identified in major Korean news reports by the surname Kang, had divorced and were involved in a dispute over his access to their son. A court permitted a visit, and the parents arranged to meet on Jeju Island on May 25, 2019.
Police concluded that Koh planned the killing in advance. Investigators cited purchases made before the meeting, online searches related to methods and cleanup, and her acquisition of the sedative zolpidem. The meeting took place at a rental pension on Jeju.
Kang did not return from the visit. Police later determined that he had been killed at the pension and that Koh had attempted to conceal what happened and dispose of his remains. His family searched for him while the investigation developed.
Investigation
Koh initially claimed that she acted in self-defense after an attempted sexual assault. Police and prosecutors rejected that account, arguing that the preparations before the meeting and the conduct afterward demonstrated premeditation.
The prosecution also charged Koh in a separate case involving the death of her current husband's young son in Cheongju. That allegation was litigated alongside the Jeju murder case, but the evidence produced a different legal result.
Trial and life sentence
In February 2020, the Jeju District Court convicted Koh of murdering her former husband and of offenses connected to concealing and disposing of his body. The court sentenced her to life imprisonment.
The same court acquitted Koh of murdering her stepson. It found that the prosecution had not excluded other possible causes of the child's death and applied the presumption of innocence. Prosecutors sought to overturn that acquittal, but the higher courts did not do so.
On July 15, 2020, the Gwangju High Court's Jeju branch upheld the life sentence for the ex-husband's murder and also upheld the acquittal in the stepson case.
Supreme Court ruling
On November 5, 2020, South Korea's Supreme Court confirmed Koh Yu-jeong's life imprisonment. The court accepted the lower courts' conclusion that the Jeju murder was premeditated and rejected her claim that the killing occurred in self-defense.
The Supreme Court also left the stepson acquittal intact, citing insufficient evidence. That distinction is essential: Koh is a convicted murderer in the death of her former husband, but she was not convicted of killing her stepson.
Timeline
May 25, 2019: Koh Yu-jeong meets her former husband on Jeju Island for a court-arranged visit involving their son; investigators later determine he was murdered that day.
June 4, 2019: Koh is arrested on suspicion of the murder.
February 20, 2020: Jeju District Court sentences Koh to life imprisonment for the ex-husband's murder and acquits her in the separate stepson murder charge.
July 15, 2020: Gwangju High Court's Jeju branch upholds both the life sentence and the stepson acquittal.
November 5, 2020: South Korea's Supreme Court finalizes the life sentence and leaves the separate acquittal intact.
Current status
The murder of Koh Yu-jeong's former husband is solved / adjudicated. Koh is serving a life sentence after the Supreme Court upheld her conviction. The separate allegation that she murdered her stepson ended in acquittal and is not treated here as a proven crime by her.
Sources
- Yonhap News Agency — Supreme Court confirms life imprisonment, November 5, 2020
- Yonhap News Agency — appellate court upholds life sentence and stepson acquittal, July 15, 2020
- Yonhap News Agency — Jeju District Court imposes life sentence, February 20, 2020
- The Korea Times — arrest and May 25, 2019 case chronology, June 24, 2019