Murder by gaslighting? Drowning in 2019 a tale of abuse, infidelity and homicide

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Murder by gaslighting? Drowning in 2019 a tale of abuse, infidelity and homicide

Published: 22 Jul. 2025, 07:00 Updated: 06 Oct. 2025, 23:42

LEE SOO-JUNG
[email protected]

Audio report: written by reporters, read by AI

Yongso Falls in Gapyeong, Gyeonggi, in April 2022, where Yoon Sang-yeop drowned after diving in June 2019. [NEWS1]

[KOREAN CRIME FILES #2]

Behind the glitz and glamour seen in pop culture, Korea’s grimmest and most harrowing crime stories, some more well-known than others, continue to haunt society today. The Korea JoongAng Daily takes a deep dive into some of these stories, sharing a glimpse into the darker side of society as well as the most up-to-date known facts. – Ed.

Seven men and women take a fun trip to escape the heat to a stream in Gyeonggi’s Gapyeong in the summer of 2019. Among them is a married couple … and the wife's lover. What starts as a fun outing to a destination famous for recreational water activities turns into a nightmare with one deadly dive.

Of the seven, six return alive.

On June 30 in 2019, 39-year-old Yoon Sang-yeop was pronounced dead after drowning. He was survived by his wife, then 28-year-old Lee Eun-hae.

Yoon's death resurfaced after a documentary from broadcaster SBS on the suspicions surrounding his drowning was televised in 2022. What unfolded was a sordid tale of a secretive affair, gaslighting allegations, suspicious life insurance policies and a watery death.

It also left a question: Was it a coincidental mishap or homicide resulting from gaslighting?

The final dive

Left: Yongso Falls in Gapyeong, Gyeonggi; Right: Relationship between two murderers Lee Eun-hae and Cho Hyeon-soo and a victim Yoon Sang-yeop [YUN YOUNG]

On June 30, 2019, Yoon joined his wife Lee Eun-hae, her lover Cho Hyeon-soo and four others on a trip to Yongso Falls in Gapyeong, a rocky stream popular for cliff diving. The seven arrived at the site at around 3 p.m.

In the afternoon, some of them swam in the stream. The others took time to unwind, enjoying their ramyeon and grilled meat. However, Yoon — who feared swimming — appeared visibly distressed throughout the outing.

At one point, Yoon was covering his face with his hands while on a flotation tube, as Cho shook the tube violently, as seen in footage obtained by cable broadcaster Channel A in April 2022. Lee reportedly asked another person to help flip Yoon into the water, saying he was “too heavy to be flipped.”

Yoon eventually climbed out of the water, but the intimidation didn’t end. Lee ordered him to smash a watermelon with his head — and he complied.

Later that evening, at around 8 p.m., other visitors and safety personnel left the site. Only Lee's group of seven remained. Lee and Cho decided to make Yoon jump from the cliff — without any safety gear or life jackets.

Images of the fateful outing to Yongso Falls in Gapyeong in Gyeonggi on June 30, 2019. The bottom right image shows the moment when Yoon Sang-yeop was cracking a watermelon with his head. [SCREEN CAPTURE]

Around 8:17 p.m., two other men in the group climbed a four-meter (13-feet) cliff to dive into the stream. Yoon followed. A witness later told another broadcaster, SBS, in 2022 that Yoon had initially refused to jump, but Lee pressured him, asking, “Are you not going to dive when all the other men are doing it?”

Cho, known among the group for his strong swimming — his nickname was “seal” — jumped first and got on a flotation tube. Yoon followed seconds later. The witness said they heard Yoon’s scream after hitting the water. Lee later claimed he made no sound at all and simply vanished.

Cho Hyeon-soo shakes a flotation tube that the late Yoon Sang-yeop was riding in a stream in Gapyeong, Gyeonggi, in June 2019. Yoon's then-wife Lee Eun-hae asked another person to shake the tube in the footage. [SCREEN CAPTURE]

Autopsy results contradicted her account. Air bubbles were found in Yoon’s respiratory tract — a sign he had been breathing above water after impact. Forensic expert Lee Ho, speaking in the SBS documentary, said the bubbles suggested he had surfaced and was conscious for at least some time.

According to the Incheon District Court's later verdict, Cho — who was about five meters from Yoon — made no attempt to help. The witness stated that Cho initially swam toward Yoon, but by the time the witness and Lee returned with a second flotation device, Cho had returned to the shore.

The call for emergency help was made at 8:24 p.m. Yoon’s body was pulled from the water at around 9:05 p.m. Forensic authorities ruled the cause of death as drowning.

Experienced plotters

From left: Lee Eun-hae and her affair partner Cho Hyeon-soo [YONHAP]

Lee and Cho were about to become partners-in-crime, and it wasn’t for want of trying. That fateful day in Gapyeong was their third attempt to kill Yoon.

Their initial try was poisoning. In February 2019, Lee and Cho mixed the poisonous blood and reproductive organs from puffer fish into a bowl of soup served to Yoon. Yoon survived because the dose was not lethal.

“Why isn’t he dying, even when I put puffer fish’s blood in it?” Lee texted Cho in a message on Telegram.

The second attempt came in May 2019. It happened in a reservoir in Yongin, Gyeonggi, late at night. Yoon believed that Lee had pushed him into the water. Yoon told her, “I know it.” This time, a witness who spotted Yoon saved his life by prompting Lee and Cho to pull him out of the water.

An image of Lee Eun-hae, left, and victim Yoon Sang-yeop in an undated photo [JOONGANG ILBO]

Lee was not afraid of losing her husband. She had Yoon’s life insurance policies, with a combined payout of 800 million won (approximately $587,230) from three separate plans.

On June 30, 2019, Yoon died just four hours before the policies were set to expire.

In the SBS documentary, an insurance company official said the monthly premiums were paid at the last minute before the policies were scheduled to be revoked due to delayed payments — a behavior to “keep the policy valid no matter what.”

However, Lee never saw a dime. The insurance company flagged the case as a potential fraud, casting doubt on Lee, who had designated herself as a sole beneficiary of the payouts. In November 2020, Lee filed a lawsuit against the insurance company. She was still pursuing the insurance payout — the same money for which her husband had lost everything and died.

Money, marriage and murder

A marriage photo of Lee Eun-hae, left, and Yoon Sang-yeop [SCREEN CAPTURE]

The beginning of tragedy dates back to 2011, when Lee and Yoon first met at a bar. They married in 2017 — but never lived together.

At the time of their wedding, Yoon reportedly had around 300 million won in savings. In 2022, the Incheon District Court stated that Lee “squandered Yoon’s fortune.”

Psychologists and forensic experts believed that Lee’s gaslighting led Yoon to use all his savings and income on her.

Crime timeline on how Lee Eun-hae prepared to murder Yoon Sang-yeop and how she was ultimately punished [YUN YOUNG]

In recorded phone calls between Lee and Yoon, provided by Yoon's relatives and obtained by broadcaster MBC, her mood swings were apparent. She occasionally talked gently but also in an irritated and angered tone with sighs.

Forensic psychologist Lee Soo-jung, who assessed Lee’s mentality at the court, noted that Lee’s erratic pattern puzzled Yoon. It made him “panic emotionally.” The psychologist also noted Lee’s behavior made Yoon “incapable of making decisions at his will,” making him entirely rely on Lee.

Criminal profiler Pyo Chang-won likened the relationship between the married couple to a hostage situation during his appearance on a TV show aired by broadcaster MBC. Pyo said Lee dangled the idea of cohabitation as a carrot on a stick to manipulate him.

“Yoon favored peace and disliked conflict, but Lee’s personality was the opposite,” Pyo said. “In this dynamic, the peace-oriented person follows what the other demands to avoid conflict. If this repeats, the person becomes psychologically dominated.”

A series of messages written from Yoon Sang-yeop to Lee Eun-hae shows that Yoon constantly begged Lee for small amount of money to feed himself. [JOONGANG ILBO]

Lee had a decent salary of around 4.5 million won per month as a corporate researcher. However, the balances in his bank accounts were less than 10,000 won just months before his death. Yoon begged his colleagues for some 3,000 won to buy ramyeon and water. He showed up at his office wearing worn-out shoes.

Yoon’s bereaved families alleged that Lee and her lover Cho had misappropriated Yoon’s savings and income — nearly 600 to 700 million won. Those funds were believed to have been funneled into Yoon’s life insurance policies. In October 2018, Yoon even handed over his interim severance pay — 37 million won — to her.

Yoon considered selling a kidney and taking his own life. In a note dated Dec. 31, 2018, he wrote that he wouldn’t be sorry — and that Lee likely wouldn’t attend his funeral because “she was always busy.”

Justice served?

Lee Eun-hae, who murdered her then-husband, left, and Lee's affair partner, Cho Hyeon-soo, walk into the Incheon District Court for questioning in April 2022. [YONHAP]

Lee and Cho went on the run for four months before being arrested in April 2022. Lee’s father allegedly persuaded his daughter to turn herself in.

In October 2022, the Incheon District Court sentenced Lee to life in prison, while Cho was given a 30-year sentence. The local court ruled that Lee conspired with Cho to kill Yoon after Yoon — drained of his cash — became useless to her. The court also noted that Lee and Cho showed no remorse and even sought financial gain by filing insurance claims.

The ruling was upheld by the Seoul High Court and, ultimately, by the Supreme Court in September 2023. In its ruling, the top court said that Lee and Cho had "murdered" Yoon by failing to take proper rescue measures, despite knowing he was drowning and was likely to die.

However, all three courts — the Incheon District Court, the Seoul High Court and the Supreme Court — rejected prosecutors’ claims that Lee and Cho murdered Yoon through an act of commission.

Yongso stream in Gapyeong, Gyeonggi. A rocky cliff where a 39-year-old victim jumped to dive is also seen in the photo. [YONHAP]

In April last year, the Incheon Family Court annulled the marriage between Yoon and Lee in a lawsuit filed by Yoon’s bereaved relatives. The court noted that Lee unilaterally “exploited” Yoon. The relatives said that they hoped to “bring peace to Yoon, even in his afterlife.”

But peace was never Lee’s concern.

From the day they married — without ever living together — to the moment she chased the insurance payout after his death, her focus remained fixed: not on her husband, but on what he was worth.

BY LEE SOO-JUNG [[email protected]]

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Murder by gaslighting? Drowning in 2019 a tale of abuse, infidelity and homicide

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