Gapyeong Valley Murder — South Korea True Crime

Editorial note: This page documents a real homicide. Crime by Region avoids graphic detail, centers the victim, and distinguishes trial findings from allegations made before conviction.

What happened

On June 30, 2019, 39-year-old Yoon Sang-yeop joined his wife, Lee Eun-hae, Lee's extramarital partner Cho Hyun-soo and several acquaintances at Yongso Falls in Gapyeong, Gyeonggi Province. Yoon could not swim. Later that evening he entered the water after jumping from a rock and drowned.

Police initially treated the death as an accident. The case was later reopened after concerns from Yoon's family and questions surrounding Lee's attempt to collect a substantial life-insurance benefit.

From accident to homicide investigation

As investigators revisited the case, they examined the relationship between Yoon, Lee and Cho, the insurance policies, and earlier incidents involving Yoon. Prosecutors eventually charged Lee and Cho with murder and with two earlier attempted killings in 2019.

The prosecution argued that the June drowning was the culmination of a plan designed to look accidental. Court reporting later established that Lee was the beneficiary of life-insurance policies worth 800 million won. The final criminal judgments found a financial motive connected to that benefit.

Earlier attempted killings

Lee and Cho were also convicted over two earlier attempts to kill Yoon in 2019. One involved puffer-fish toxin in February. Another involved an effort to drown him at a fishing location in May. He survived both incidents.

These attempts mattered to the later case because they helped establish that the fatal drowning was not examined in isolation. The courts considered a sequence of conduct directed at Yoon before his death.

Arrest and prosecution

Lee and Cho fled after being questioned by prosecutors in December 2021. Prosecutors publicly sought them in March 2022, and police arrested both in Goyang on April 16, 2022. They were subsequently detained and brought to trial in Incheon.

Trial and Supreme Court outcome

Incheon District Court convicted Lee and Cho in October 2022. Lee received life imprisonment and Cho received a 30-year prison term. The appellate court upheld those sentences in April 2023.

On September 21, 2023, South Korea's Supreme Court left the sentences in place: life imprisonment for Lee and 30 years for Cho. The final ruling also preserved their convictions for the earlier attempts on Yoon's life. Crime by Region therefore lists the case as solved and fully adjudicated.

Why the case drew national attention

The case became widely known because the death had initially appeared accidental and was reexamined only after persistent concerns. It also raised public interest in insurance-motivated homicide, coercive relationship dynamics and the difficulty of reconstructing intent in a death that occurs in an outdoor recreational setting.

Some commentary has described the relationship using the term “gaslighting.” Because that term can blur psychology, media framing and legal findings, this page does not treat it as a separate criminal fact. The core adjudicated findings are the murder, the earlier attempted killings and the sentences imposed on Lee and Cho.

Sources and further reading

Archive context

This case is included in the South Korea archive. For other adjudicated Korean cases, see The Hwaseong Serial Murders, The Daegu Subway Fire and The Chijon Family Murders.