Jeong Nam-gyu was 37 when he was caught, in the early hours of April 22, 2006, inside a house in Yeongdeungpo-gu, in southwestern Seoul. He had broken in and struck a sleeping man in his twenties, and the man and his father fought him and held him for police. He was booked as a robber. Within days, investigators had tied him to a run of killings and attacks that had gone on across southwestern Seoul and the neighboring province of Gyeonggi for more than two years.
Korean press accounts give the total as 13 people killed and 20 seriously injured between January 2004 and April 2006. His victims were strangers: two schoolboys in Bucheon, women walking home alone at night, and people asleep in their own homes. The Seoul Southern District Court sentenced him to death on September 21, 2006, and the sentence became final in April 2007. South Korea had stopped carrying out executions in 1997, and Jeong was still held at the Seoul Detention Center when he hanged himself in his cell in November 2009. He died the next morning, aged 40.
Jeong was born in 1969. One Korean account, published in 2025 by the Sidae news outlet, gives his birthplace as Jangsu County in North Jeolla province. Money Today, in a 2025 retrospective, said he grew up in a farming family in a rural village in the same province, the seventh of nine children, five sons and four daughters.
Every recent Korean account of his early life tells the same story of violence at home and outside it. His father beat him repeatedly. When he was in the fifth grade of elementary school, a man from the neighborhood sexually assaulted him; Money Today reported that he admitted to police that the event had shaped him strongly. In high school he was bullied by groups of other students, and during his military service he was beaten and mistreated. The Seoul Shinmun, in a 2026 account of the case, wrote that he blamed his crimes on those experiences. None of the accounts suggests that any of his victims had anything to do with them.
By the time of the killings he was living in Incheon, west of Seoul. Money Today reported that on the night of the first killings he had been at home in Incheon before he went out.
Jeong had been in and out of prison for most of his adult life. According to The Sisa Law, a legal news outlet, his first conviction came in 1989, for aggravated robbery, and he received two years and six months, suspended for four years. In 1996 he was charged with robbery, with other charges; Money Today reported that his first trial ended in a suspended sentence and that on appeal he received two years and six months in prison. In 1999 he was convicted of theft, with other charges, and sentenced to two years. In 2002 he was convicted of car theft and served ten months.
The series began in Bucheon, a city in Gyeonggi province between Seoul and Incheon. On the evening of January 14, 2004, two boys, aged 13 and 12, went out to play ball near their homes in Wonmi-gu. At about 8:50 p.m. the older boy called his younger sister from a pay phone and told her he was heading to a PC room near home where their mother was. That was the last time anyone in their families heard from them. A classmate later told police that at about 10 p.m. he had seen the two boys following an adult man.
Police mounted a large search around the place they were last seen. On January 30, 2004, sixteen days after they disappeared, the boys were found dead in Bucheon. The National Forensic Service concluded that both had been strangled on the day they vanished. The investigation stalled, and for more than two years nobody was charged.
After his arrest in 2006, Jeong confessed to the killings during questioning. Money Today reported in 2026 that he told investigators he had been at home in Incheon when he felt an urge to kill, rode buses for a while, and came across the two boys. Prosecutors went back over the investigation files of the local police station and indicted him on the strength of a detailed account that, they said, only the person responsible could have given, and of the consistency with which he claimed the crime as his own.
The attacks that followed were on adults, most of them women. Money Today, citing the case record in its 2025 and 2026 retrospectives, reported that on January 30, 2004, he stabbed a woman in her forties in Guro-gu, Seoul, leaving her seriously injured. (A second Money Today account placed this attack on the same day as the Bucheon killings.)
On February 6, 2004, he stabbed a 27-year-old woman surnamed Jeon to death on a street in Imun-dong, in Dongdaemun-gu, in northeastern Seoul. The Hankook Ilbo listed her killing first among the charges the court considered in 2006. Her death had already been claimed by another man. Yoo Young-chul, sentenced to death in 2005 for 20 killings, had told investigators he killed a woman in Imun-dong. His first-instance court left that killing out of his convictions, and prosecutors appealed, unsuccessfully, to the Supreme Court in 2005, according to Weekly Kyunghyang. After Jeong's arrest, police established that he was the man responsible for the Imun-dong killing, Money Today reported in 2009.
Jeong was angry that Yoo had taken credit for the killing, according to the Seoul Shinmun and the Seoul Economic Daily. He told investigators that Yoo was a step below him, and he claimed to be better at avoiding capture.
Over the following months he attacked roughly once a month across Seoul and Gyeonggi, Money Today reported. Early in the series he went for women walking home alone at night, using a knife. The Seoul Economic Daily reported that, unlike many offenders, he often attacked in fairly bright places, under streetlights or the lights of shops.
Jeong planned around the cameras that had helped catch Yoo Young-chul. He kept away from Gangnam and other areas with many closed-circuit cameras and chose neighborhoods where security was thin, Money Today reported. He moved on foot, and before and after an attack he walked or ran several kilometers so that cameras would not pick up his route, according to the Seoul Shinmun. He cut the soles of his shoes so that they would not leave clear footprints, and Weekly Kyunghyang reported in 2006 that he switched among several pairs of sneakers to confuse investigators.
He also trained for it. He gave up drinking and smoking, according to the Seoul Economic Daily, and ran about ten kilometers a day; Money Today quoted him as saying he needed to stay healthy so that he could go on killing. Police found newspaper clippings about his crimes and forensic science magazines in his home, the Seoul Shinmun reported.
The Sidae outlet wrote that he kept southern Seoul in fear for about two years. Because several of the attacks fell on rainy nights, the series became known in the press as the "rainy Thursday night" case, and newspapers compared it to the film Memories of Murder, based on the Hwaseong killings of the 1980s, calling it a Seoul version of that story, according to Money Today and the Seoul Shinmun.
From 2005, Weekly Kyunghyang reported, Jeong changed his approach and began breaking into homes. He chose houses in working-class neighborhoods and attacked people while they slept, striking them with blunt objects. In some cases he set fire to the home. The Seoul Economic Daily reported that he broke into 11 homes in all, and that 7 of the dead and 11 of the seriously injured were victims of those home invasions.
Among the cases was an attack on three sisters at their home in Bongcheon-dong, in Gwanak-gu. A news photograph taken on April 24, 2006, two days after his arrest, showed him being taken into Yeongdeungpo Police Station as the suspect in what the press called the killing of three sisters in Bongcheon-dong, the Seoul Shinmun reported in 2026.
The victims of the home attacks were mostly women, but not all. The young man whose resistance ended the series in April 2006 was the son of the family in the house, and Money Today's 2026 account of the series said that, besides women, he went after middle-aged men. Another Money Today account, published in April 2026, said none of his victims were men, which does not fit the accounts of his arrest.
Korean reporting has published little about most of the people he killed beyond their ages, the districts where they lived and the dates of the attacks. The court that sentenced him described them as women walking along the street, people asleep in their own homes, and children who had been playing with friends.
The end came in the early morning of April 22, 2006. Jeong broke into a multi-unit house in Yeongdeungpo-gu, took 24,000 won, and struck a sleeping man in his twenties with a blunt object, according to the Seoul Economic Daily. The man woke and fought back. His father joined in, and together they subdued Jeong and handed him over to the police.
Even then he nearly got away. Though handcuffed, he pushed past the officers and ran, the Seoul Economic Daily reported. He hid on a rooftop about 15 meters away and was caught again after a resident reported him. In his bag police found the tool he had used, a mask, rubber-coated gloves and shoes with damaged soles.
At first the police treated him as an ordinary burglar who had injured someone in a robbery. On the way to the station he said that he should have killed a thousand people and that he had failed to commit the perfect crime, the Seoul Economic Daily and Money Today reported. Other accounts quote him as saying he was unhappy not to have reached his goal of a thousand, and that he still wanted to smell blood.
What turned a burglary into a murder inquiry was the questioning that followed. Kwon Il-yong, then head of the crime behavioral analysis team in the National Police Agency's forensic investigation bureau, interviewed him, and Jeong's other crimes came to light through that interview, Financial News reported in 2020. Kwon is described in Korean press as the country's first criminal profiler. Yonhap reported in 2010 that he had drawn out confessions to further crimes from several serial killers, Jeong among them, and a 2013 profile in the Kyeonggi Ilbo listed the Jeong case of 2006 among the cases his work had helped to solve.
Kwon later said that Jeong showed no interest in reducing his punishment. In interviews quoted by the Sidae outlet, Money Today and the Seoul Economic Daily, Kwon said that Jeong was driven by the urge to kill, took pleasure in it, and seemed to relive his crimes with satisfaction as he described them. Kwon classified him as a pleasure-driven offender who gained gratification from watching his victims suffer, the Seoul Economic Daily reported, and described him as cowardly, strong toward the weak and careful to hide from the strong. In 2020 Kwon told Financial News that he had interviewed about a thousand criminals and considered Jeong the most brutal of them.
Police found that he had no motive of money or revenge, according to the Seoul Economic Daily. He told investigators that on days when he killed he felt bad from the morning onward and that only killing relieved it; afterward, he said, his mind was clear and his depression and inner conflict were gone. The Kyeonggi Ilbo, writing in 2013, gave his stated motive as hatred of the world.
Jeong did not behave like a man trying to save himself. During the police reconstruction of one of the crimes, a relative of a victim threw a flowerpot at him, and he tried to throw a clothes-drying rack back, Financial News reported; the scene caused public anger. In the police vehicle he smiled at the news cameras.
Prosecutors indicted Jeong in custody on June 7, 2006, Money Today reported in 2009. His case went to the Seoul Southern District Court. Weekly Kyunghyang reported in August 2006, after his first hearing, that he had told the court that the urge to kill came over him like the urge to smoke a cigarette, that he still felt it, and that he was frustrated and restless because he was held in solitary confinement and could not kill. He said he had not thought about his victims' pain. He also said, in a line still quoted in Korean coverage, that he could quit smoking but could not quit killing. Money Today reported that he behaved erratically in court and at one point rushed toward the prosecutors' seats.
On September 21, 2006, the 11th Criminal Division of the Seoul Southern District Court, presided over by Judge Lee Tae-seop, sentenced him to death. The Hankook Ilbo reported that the case covered 25 offenses, including robbery with injury and murder, committed in western and southwestern Seoul between 2004 and April 2006, in which 13 people died and 20 were seriously injured.
The judges said that he had expressed only frustration with his own bleak life and showed no remorse, and that he was likely to commit similar crimes if he returned to society. The victims had no relationship with him. His motive, the court found, was not money or sexual gratification but a wish to vent his anger at society and to find satisfaction in killing and in setting fires. Given all the circumstances, the judges said, the most severe penalty was unavoidable.
Asked for a final statement, Jeong said that his life had gone wrong somehow, and that if the state and society had helped him the tragedy would not have happened, the Hankook Ilbo reported. Money Today added that he said cruel and brutal violence had made him what he was. He did not bow his head at the verdict, according to the Seoul Economic Daily.
Jeong appealed. The appeals went up to the Supreme Court, which ruled on April 12, 2007, and the death sentence became final, Money Today reported in 2009 and again in 2026. The Sidae outlet put the length of the trial at about a year. From custody he wrote letters to the court in which he showed no remorse for his victims and said he had enjoyed killing, The Sisa Law reported.
By then South Korea had carried out no execution for almost a decade. The last executions took place on December 30, 1997, when 23 people were put to death, according to Money Today; Weekly Kyunghyang had reported in 2005 that executions were unlikely in the near term because of public opinion and growing calls for abolition. Reuters noted in 2009 that Kim Dae-jung, who had himself once been sentenced to death under military rule, was elected president the same month as the last executions.
As a condemned prisoner who had not been executed, Jeong was classed as a detainee rather than a convict serving a sentence, and he was held in a solitary cell at the Seoul Detention Center rather than in a prison, Money Today explained in 2025. The detention center is in Uiwang, in Gyeonggi province, The Korea Times reported. Several accounts say he struggled with his urge to kill while in custody.
He kept writing to Kwon Il-yong. According to Kwon, quoted by Financial News in 2020, the letters said that Jeong was frustrated at being unable to kill while locked up, and asked either to be executed or to be released.
At about 6:35 a.m. on Saturday, November 21, 2009, Jeong hanged himself in his cell at the Seoul Detention Center with a cord he had made by twisting plastic garbage bags together, Money Today reported the next day. The officer on duty found him and gave first aid. He was taken to a nearby hospital, examined and admitted to intensive care. His condition worsened around midnight, and he died at about 2:35 a.m. on November 22. He was 40. Reuters, quoting a Justice Ministry official, reported that he died of a heart attack in hospital the day after he was found, and that suicide was suspected but no will had been found.
There was no suicide note. Officials found a memo in his notebook that, The Korea Times reported, referred to the government not considering abolishing the death penalty; the Seoul Economic Daily described the notebook as also containing the remark that life is like a passing cloud. The Ministry of Justice suggested that uncertainty about his execution may have contributed to his death, and an autopsy was requested, The Korea Times said.
Only his brother-in-law attended his wake, according to Money Today, which reported that his family had rejected him. His body was cremated.
His death raised questions about how death-row inmates were watched. His cell had no surveillance camera. The Korea Times reported that cameras had been removed from cells after a revision of the rules that followed campaigns by human rights groups, which had called the cameras an invasion of privacy, and that until then death-row inmates had been watched by camera around the clock. Only a skeleton crew was on duty that weekend, and a guard needed about 15 minutes to tour a block of 70 to 100 inmates; officials said that gap gave Jeong his chance.
Critics said the detention center had handed out recycled garbage bags without seeing the risk, and had failed to supervise him, Money Today reported. The Ministry of Justice said the attempt could not have been prevented and that it would be hard to hold the detention center responsible, but it promised to strengthen the treatment and custody of death-row inmates. The Korea Times put the number of convicted prisoners who had killed themselves in custody since 2004 at 82, and reported that South Korea had the highest rate of suicide among inmates of any OECD country.
Kwon Il-yong later said that the death was not a simple suicide but Jeong's final murder, in which the victim was himself, Financial News reported. In Kwon's view, as reported by the Sidae outlet, Jeong never apologized to the families of the people he killed.
The figure of 13 dead and 20 seriously injured is the one given by the Hankook Ilbo's report of the 2006 verdict and by most later Korean accounts, including Money Today, the Kyeonggi Ilbo, Weekly Kyunghyang, The Sisa Law and the Seoul Economic Daily. Reuters, in 2009, wrote that he had been sentenced to death for murdering 13 people and was also charged with crimes against 20 others who survived with injuries. The Korea Times, reporting his death, said the 13 dead included two minors.
The number of separate crimes is reported differently. The Hankook Ilbo counted 25 offenses in the 2006 case; Money Today, in April 2026, described 24 crimes in all. Accounts also differ on the length of the series, given variously as about 27 months, two years and four months, and two years and five months, all for the same period from January 2004 to April 2006.
Jeong's own claim that he could have killed a thousand people was a boast, not a record; no account attributes more than 13 deaths to him. His claim that the Imun-dong killing was his, rather than Yoo Young-chul's, was accepted by police and was among the charges on which he was sentenced, according to the Hankook Ilbo. Accounts of his childhood and of the abuse he suffered rest on what he told investigators, as retold in later press accounts.
Some Korean retellings of the case give details of the early investigation and of individual attacks that do not appear in the reports of his trial, and some differ from each other on dates and on whether men were among his victims.
1969: Jeong Nam-gyu is born in North Jeolla province.
1989: First conviction, for aggravated robbery; suspended sentence.
1996 to 2002: Prison terms for robbery and theft, with other charges, and for car theft.
January 14, 2004: Two boys, 13 and 12, disappear from a playground in Bucheon; they are found dead on a hillside on January 30.
January 30, 2004: A woman in her forties is stabbed and seriously injured in Guro-gu, Seoul.
February 6, 2004: A 27-year-old woman surnamed Jeon is stabbed to death in Imun-dong, Dongdaemun-gu.
2004 to 2005: Street attacks on women across southwestern Seoul and Gyeonggi.
From 2005: Attacks inside homes, some followed by fires.
April 22, 2006: Arrested in Yeongdeungpo-gu after a young man and his father overpower him; escapes briefly while handcuffed and is recaptured.
April 24, 2006: Taken into Yeongdeungpo Police Station as the suspect in the killing of three sisters in Bongcheon-dong, Gwanak-gu.
June 7, 2006: Indicted in custody.
September 21, 2006: Sentenced to death by the Seoul Southern District Court.
April 12, 2007: The Supreme Court rules; the death sentence becomes final.
November 21, 2009: Hangs himself in his cell at the Seoul Detention Center.
November 22, 2009: Dies in hospital at about 2:35 a.m., aged 40.