Lee Choon-jae

On September 18, 2019, police announced that Lee had been identified as a suspect in the serial murders. He was identified after DNA from the underwear of one of the victims was matched with his, and subsequent DNA testing linked him to four of the other unsolved serial murders. At the time, he was identified he was already serving a life sentence at a prison in Busan for the rape and murder of his sister-in-law. Lee initially denied any involvement in the serial murders, but on 2 October 2019, police announced that Lee had confessed to killing 15 people, including all 10 victims in the serial murders, which includes a case previously considered to be a copycat crime, and 5 others. Three of those other murders happened in Hwaseong but had not previously been attributed to the serial killer, and the other two happened in Cheongju. As of October 2019, details about those 5 victims have not been released because the investigation is ongoing. In addition to the murders, he also confessed to more than 30 rapes and attempted rapes.

On 15 November 2019, police announced that they had reached a provisional conclusion that Lee was responsible for all 10 serial murders.

Yoon Sang-Yeo, who was convicted of killing the eighth victim and spent 20 years in prison until he was released on parole in 2009, filed for a re-trial of his case on 13 November 2019 following news reports that Lee had confessed to all 10 serial murders. Two days later, police announced that they had reached a provisional conclusion that Lee was responsible for the murder for which Yoon was convicted. Police said Lee's confession in the eighth murder 'elaborately and coherently' described both the scene and the victim. This raised concerns that police had charged an innocent man.

The release of the film Memories of Murder in 2003, which was partially inspired by the serial murders, sparked renewed interest in the case. The murder of a female college student in Hwaseong in 2004 also sparked renewed interest and fears that a serial killer had returned. The serial murders made headlines again as the statute of limitations for the most recent victims was due to expire on April 2, 2006. At the time of the killings, there was a 15-year statute of limitations for first-degree murder. This was increased to 25 years in 2007, and finally lifted in 2015, but it was not retroactive. However, evidence and police records were kept due to the significance of the case.

The serial murders are considered to be the most infamous in South Korea's modern history. They are often compared to those committed by the Zodiac Killer in the United States, and served as the inspiration for the 2003 film Memories of Murder. Lee was sentenced to life imprisonment with the possibility of parole after 20 years in the killing of his sister-in-law, but despite DNA evidence and his confession in 2019, he could not be prosecuted for the other murders because the statute of limitations had expired.

After Lee's wife left him in December 1993, he invited over his 18-year-old sister-in-law, then proceeded to drug, rape and kill her on January 13, 1994. According to the detective who investigated him, Lee went to his father-in-law offering help in the search for his missing sister-in-law, where they both reported that she might have been abducted. Lee was arrested a few days later, on January 18, after repeated questioning where he later asked, " How many years do you serve in prison for rape and murder?" Lee denied any responsibility and the court overturned his confession, stating that he made a false statement because of police coercion. However, Lee was convicted and sentenced to death in May 1994, and his conviction was upheld in September of the same year. The Supreme Court of South Korea reviewed the case in 1995 and Lee's sentence was reduced to a life sentence, with the possibility of parole after 20 years.

On July 27, 1989, Yoon Sang-Yeo, a 22-year-old man, was arrested for the murder of the eighth victim, 14-year-old Park Sang-hee. Yoon admitted guilt during questioning and forensic tests of pubic hair samples found at the scene suggested similarities with his. This case was determined to be a copycat crime, and Yoon was sentenced to life in prison, but appealed the ruling at the time, alleging that police coerced him into giving false confessions through torture. His appeal was denied and he served 19.5 years in jail before being released on parole in 2009. In 2019, Lee Choon-jae confessed to the murder and Yoon filed for a re-trial to prove his innocence.

On September 26, 1989, around 0:55 am, Lee broke into a house in Gwangju, Suwon, Gyeonggi Province with weapons and gloves and was discovered by the landlord. He was sentenced by the Suwon District Court to one year and six months in prison in the first trial in February 1990 for the charges of robbery and violence. After the first trial, Lee filed an appeal, claiming that he was beaten by an unknown young man and entered the victim's house while being chased. In the second trial following Lee's appeal, the court suspended his sentence to two years of probation, where he was released in mid-April, 1990.

A suspect sketch was drawn based on the memory of the bus driver, Kang, and bus conductor, Uhm, who saw a man get on the bus shortly after the seventh murder on September 7, 1988. The characteristics of the suspect, which were described by the bus driver, were similar to the descriptions given by survivors who were sexually assaulted. According to the victims, the culprit at the time of the incident was a thin-framed man in his mid-20s, with a height of 165 to 170 centimeters, a short cut sporty-type hair, no double eyelids, and a sharp nose. In addition, he was described as having soft hands. Police also stated that the suspect had a "B" blood type, but in 2019, police acknowledged that this was likely inaccurate, because Lee has blood type "O".

The Hwaseong serial murders (Korean: 화성 연쇄 살인 사건 ; Hanja: 華城連鎖殺人事件 ; RR: hwaseong yeonswae sarin sageon) were a series of rapes and murders that occurred in the city of Hwaseong between September 15, 1986 and April 3, 1991. In each case, a woman was found bound, gagged, raped and in most cases strangled to death with their own clothes. It sparked the largest criminal case in South Korea with over 2 million man-days spent on investigation and over 21,000 suspects investigated.