DNA technology solves decades-long unsolved mystery of serial murder in South Korea

SEOUL, South Korea -- Advancement in DNA technology has helped police catch a murderer, solving a series of mystery cases that took place between 1986 to 1991.

The killer, Lee Chun-jae, confessed to the murder of 14 victims after detectives extracted DNA from the evidence left at the crime scene using recently developed DNA restoration technology.

Based on the identified DNA, police compared it with the DNA database of inmates at the penitentiary. The prisoner DNA database was put together in 2010, according to police.

It turned out Lee, who is in his 50s, has been in prison with a life sentence for the past 20 years for the rape and murder of his sister-in-law.

In September, South Korean police pegged Lee with at least three killings of the notorious serial murder case in Hwaseong, a rural town South of Seoul. Since then, police have carried out a daily face-to-face investigation. Veteran profilers talked to him and police pressured him with the DNA test results pointing to him as the real criminal.

Last Friday, Lee not only admitted to the accused murder but also confessed to having committed 5 more murders and 30 other rapes and attempted rapes. Police are trying to confirm the facts based on his confession.

“Suspect claims that he is responsible for the incident that the police concluded as a copycat crime in 1988, the police are investigating on the reliability of his statement,” an official from Gyeonggi South Provincial Agency told ABC News.

When the verification process ends, it will put an end to some of the most heinous unsolved crimes in South Korea. The serial murder case is known to have mobilized the largest manpower in South Korea’s investigation history, as over two million (2,050,000) police officers were committed to solving the case. Experts say that the absence of scientific investigation left the case unsolved for decades.

“This case signals a victory of scientific investigation and proves that there is no perfect crime,” Lee Soo Jung, forensic psychology professor at Seoul-based Kyonggi University told ABC News.

The statute of limitations on the serial murder case ran out in April 2006, so even if the suspect is determined to have the criminal, the justice department cannot convict him guilty of the serial killing.

ABC News' Joohee Cho contributed to this report.