The Jeju Ex-Husband Murder Case is one of the most brutal crimes. It was so meticulously planned; the killing method, disposal of the body, and destruction of evidence go beyond the imagination of ordinary people, such that even criminal experts have been discussing this case.
Koh Yu Jeong was born in 1983 and is the oldest of three, with two younger brothers. She lived a comfortable life without worrying about money and graduated from a local humanities high school. Her classmates remember her as someone with an ordinary but sweet and lively personality. She entered the Department of Chemistry at Jeju National University, where she met her soon-to-be husband Kang, whom she dated for six years before they finally got married in 2013, and gave birth to a son.
However, their marriage didn’t last. In 2017, Kang filed for divorce, citing spousal abuse as grounds. Koh countered his allegation by accusing Kang of alcohol addiction and absence, even if Kang did not consume alcohol.
Kang wanted to take custody of his son but lacked financial means and was still pursuing a doctoral course at Jeju National University. The court then ruled in favor of Koh, believing that it was in the child’s best interest to be with his mother, though Kang was allowed to visit his son twice a month.
Kang worked part-time and put together his earnings with his graduate school research allowances to provide ₩400,000 KRW (about $283 USD) for monthly child support payments. Koh did not allow Kang to see their son, even after she remarried a civil servant in Jeju and left her son with her parents to live with her new husband in Cheongju, North Chungcheong Province.
Kang filed a domestic lawsuit against his ex-wife out of desperation to see his child. The court found Koh in contempt of the law and ordered her to pick a date to let Kang see his son. On May 25, 2019, Koh returned to Jeju Island to meet with Kang in a vacation rental place, allowing him to see his son for the first time in two years.
By May 27, Kang’s younger brother was worried because Kang had not gotten in touch with him for two days. He contacted the police, fearing foul play. The police got in touch with Koh since she was the last person Kang was supposedly with.
Koh cried to the police, saying Kang attempted to sexually assault her on the night of May 25. She claimed to resist his advances, and he ran away, not returning to the vacation rental. When asked to come to the station to make a statement, she said she was no longer in Jeju but shared text messages between her and Kang, claiming she threatened to report Kang for sexual assault, to which he apologized and reasoned that he was shocked she remarried. She said Kang’s family reported him to have attempted suicide two hours later.
The police tracked Kang’s phone to a neighborhood miles away from the vacation rental and found his car in front of a supermarket but did not investigate the vehicle or the black box inside it. Since the vacation rental had no security cameras, the police investigation could not continue.
Kang’s younger brother did his investigation and forwarded to the police CCTV footage from a building near the vacation rental where Kang was last seen. Kang entered the vacation rental in the footage but did not leave. Koh, however, went to the vacation rental afternoon of May 26 with their son, came back alone, and left on the morning of May 27, supposedly the last day of their stay. She had two large bags with her and threw away two bags of garbage into the trash.
The police, by now, realized something suspicious about Kang’s disappearance. Despite this, they did not suspect Koh of anything because she cooperated with them.
On May 31, 2019, four days after Kang’s disappearance was filed, the police entered the vacation rental where Kang was last seen. The Luminol test showed massive amounts of blood on the bathroom floor, the living room, the kitchen, and the bedroom ceiling. The police arrested Koh for the murder of her ex-husband Kang the next day.
Under police custody, Koh changed her story, saying Kang tried to assault her while cutting a watermelon, so she stabbed him in self-defense. On June 4. the forensics team took pictures and samples at the vacation rental.
When the vacation rental owner realized what was happening, they protested the police presence and asked permission to clean the house. Unfortunately, the police agreed, as it would be evidence later that they grossly mishandled the investigation of Kang’s murder.
When Koh’s husband Hong visited her in jail, he found it strange that she asked if the police had taken her pouch. He searched for the pouch and found a prescription for Zolpidem, a sedative for insomnia. He submitted the pouch as evidence to the police.
On June 9, four days before her arrest expired, the police confirmed that Kang’s blood sample tested positive for Zolpidem. If Hong had not submitted the pouch as evidence, the police would not have known about Zolpidem, and Koh would have been let go.
The police finally put together a chronological string of events leading to the murder of Kang. On May 9, after the court mandate for Kang’s visitation rights, Koh searched these terms on her phone; sedatives, fatal dose of nicotine, taser, incinerator, grinder, the weight of bone, and travel bags. She secured a prescription for seven days’ worth of zolpidem for her insomnia on May 17. A saw and other tools were in her car to assist in her murder.
The vacation rental owner also confirmed that Koh requested she, Kang, and their son would be undisturbed during their stay. It was also quite a coincidence that this vacation rental had no security cameras.
Three days before she and Kang would meet, Koh went to a supermarket and bought a knife, bleach, cleaning supplies, and rubber gloves.
Koh met with Kang on May 25 at a theme park with their son. They went to a supermarket after to buy food and left Kang’s car in the supermarket’s parking lot, where the police found it later. That night, Koh prepared curry for dinner and, presumably, put the zolpidem in Kang’s food. Kang missed a call from his younger brother by 9:16 in the evening.
Koh told her son to stay and play video games in another room as Kang went to lie down. Based on the evidence and blood patterns, Koh repeatedly stabbed Kang, who woke up, ran to the kitchen and the door out of the vacation rental, and succumbed to his wounds.
Around 9:50 in the evening, the vacation rental owner called, and in the recording of that call, Koh was heard telling her son playfully, “Go to bed. I’ll be there after I clean up.” She dropped off her son at her parents’ place the following day before returning to the vacation rental.
It was assumed she butchered Kang’s body after that. Kang was 180 centimeters and eighty kilograms. After she was done with him, she fit him into two carry-on bags she bought to dispose of his body, hurting her right hand with the saw she used. She had her hand treated at a nearby clinic.
Around 4:50 in the afternoon of May 27, she faked a text conversation between her phone and Kang’s, which she shared later with the police when they called her on May 27 while she was then booked in a Jeju motel.
On May 28, she threw garbage in the back of a ship around 8:30 in the evening. She also ordered an electric saw shipped to her parents’ house in Gimpo. On her drive to Gimpo, she made stops to dispose of additional bags of evidence. On May 29, Koh purchased a ladder, some tarp, and a cleanroom suit assumed to be purchased to avoid blood splatters. She threw away her husband’s mutilated pieces in the trash and then droved to Cheongju to her current husband, Hong.
Koh was arrested on June 1 for the murder and mutilation of her ex-husband Kang’s corpse. Her identity was revealed to the public upon the request of Kang’s family due to the violence of her crime and the sufficient evidence against her.
Her defense tried but failed to say Kang was a sexual predator who attempted to sexually assault her, garnering widespread criticism from the media and the public.
The prosecutors presented overwhelming evidence of her guilt through the presence of the victim’s blood in Koh’s car and on the saw used to mutilate his corpse. Zolpidem in his blood also cast doubt on Koh’s claim that she murdered Kang in self-defense.
The Prosecution concluded that Kang’s murder was premeditated and demanded the death penalty. The court found Koh guilty of the murder of her ex-husband Kang on February 20, 2020 and sentenced her to life in prison.
Kang’s body was never found. The family went about his funeral with seven hairs they gathered from Kang’s favorite cap.