Misadventure or murder? Death of a Korean hip-hop icon 30 years ago remains a mystery. 

[KOREAN CRIME FILES #20]

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.

Singer and rapper Kim Sung-jae, formerly of the hip-hop duo Deux, was already a star when he made his solo debut on Nov. 19, 1995, appearing on an SBS music program.

It was Kim's last appearance on stage.

The day after his appearance, his agent found him unresponsive in a hotel room in western Seoul. His lips were blue. The agent called an ambulance, but the singer was confirmed dead at a nearby hospital.

He was 23 years old. How he died remains a mystery.

While he had no major wounds or scars, 28 needle marks were found on his right arm, even though he was right-handed. This sparked speculation that Kim's death was not the result of a self-administered overdose but of foul play.

Death of a Korean hip-hop icon

Kim's sudden death made headlines, as he was an icon of Korean hip-hop alongside fellow Deux member Lee Hyun-do, a close friend of his from high school.

Kim's charismatic stage presence and dance style, coupled with the R&B beats Lee helped shape, propelled the duo in the music industry, which had been more focused on ballads at the time.

Kim's death shocked fans and music industry figures alike. Indeed, his passing continues to reverberate, with veteran singer Yoon Jong-shin marking the 30th anniversary of his death with a poignant social media post in 2025.

Countless fans have similarly honored the late singer since his death.

Suspicion falls on Kim’s girlfriend

An autopsy revealed that the singer had died from an overdose of Zoletil, a veterinary anesthetic that can slow or stop breathing if taken in excessive doses.

Police pinpointed Kim's girlfriend of two years — also surnamed Kim — as a suspect after learning that she had purchased Zoletil from a veterinary hospital to euthanize her dog.

She was also with Kim at the hotel alongside seven other people the day before the singer’s death. Against this backdrop, authorities launched a probe and arrested her on Dec. 7, 1995.

“The suspect bought a set of veterinary anesthetics, 7 grams [0.2 ounces] of magnesium sulfate and two disposable syringes from a veterinary clinic in Seocho District, southern Seoul, in early November [of 1995],” police said. “The anesthetic contained the same substance that was found in Kim Sung-jae’s body.”

Police also concluded that she told Kim the injections were for fatigue, then injected the veterinary anesthetic into his right arm 28 times, causing a fatal overdose.

His girlfriend denied the allegations and said that she left the hotel after the singer fell asleep. And yet, police referred the case to the prosecution in December that year, marking the beginning of a legal battle that ended in turmoil.

Convicted at first

In the first trial, which ended in June 1996, the Seoul Western District Court convicted the girlfriend of murder and sentenced her to life in prison, citing her purchase of Zoletil before the incident.

As for the motive, the court said she murdered Kim when he tried to break up with her "so that she could have him forever."

However, an appellate court acquitted her in November 1996, with the bench noting that she had no clear motive, that one vial of Zoletil could not cause death and that another person may have entered the room and committed the crime.

The Supreme Court upheld that ruling in February 1998, clearing the girlfriend of all charges.

The authorities have yet to find any other suspects.

The media have criticized the police for their insufficient early investigation, with some outlets pointing to a lack of concrete evidence even before the first trial began.

“The girlfriend strongly denied the allegations, and the police have still not secured any physical proof other than circumstantial evidence,” the Korean daily Hankyoreh reported on Dec. 9, 1996.

Lack of evidence

The girlfriend's purchase of Zoletil before Kim Sung-jae’s death was the main reason authorities concluded she was the culprit.

However, that alone was not enough to prove her guilt, as anyone could buy the drug.

Nor was there concrete evidence that she injected Zoletil into the singer’s body when the investigation began.

The appellate court also ruled that the amount of the drug the girlfriend had bought was not enough to kill someone.

“If the defendant were the culprit, she would not have purchased a lethal drug from a veterinary hospital she knew well,” the court wrote.

The court cited several other reasons for her acquittal, including the possibility that people who were with the singer at the hotel or an outside intruder could have committed the crime.

As for the 28 needle marks on Kim’s right arm, the court found insufficient evidence that Kim's girlfriend was involved.

The amount of urine found in Kim’s body also contributed to the acquittal.

About 10 milliliters (0.3 ounces) of urine suggested he had likely urinated roughly 20 minutes before death, as the average person creates a minimum of 1 milliliter of urine per two minutes. Since there was no sign of urination at or after death, this helped the court estimate the time of his death.

“It is doubtful that the victim could have received 28 injection marks within 20 minutes of urinating without any resistance,” the court wrote. “If some of those marks were inflicted before the victim’s final urination while he was still alive, the court cannot rule out the possibility that the death was accidental.

“Even though there was no evidence supporting the charges, the lower court convicted the defendant based on records expressly cited in its judgment, thereby unlawfully finding the defendant guilty without evidentiary support.”

Failed revisit

A recent opportunity to reexamine the case was blocked by Kim's ex-girlfriend, who filed for an injunction in August 2019 to stop SBS from airing an episode about Kim’s death on its investigative program “Unanswered Questions” (1992–).

SBS said at the time that it intended to “explore institutional alternatives for solving cold cases using new scientific evidence,” but the court accepted the ex-girlfriend’s injunction motion.

“This broadcast is likely to cause serious and irreparable harm to her private rights and reputation,” the court said.

SBS attempted to air the episode again in December of the same year, but the court granted the ex-girlfriend’s injunction motion to halt the move.

The public knows little about Kim’s ex-girlfriend, except that she was born in 1970 and is still alive.

Kim is survived by his mother and younger brother as of 2026. Deux member Lee released a song titled “Rise” (2025) using Kim’s AI-generated voice in November 2025.

The song was Deux’s first in 28 years, with agency J, Wide-Company calling it a “new start for Deux.” Lee most recently released another ballad, “Another Day,” on April 18, telling the story of longing for the departed and of unchanging friendship.

The date coincided with Kim's birthday. He would be 54 if he were alive today.

BY PAIK JI-HWAN [[email protected]]