South Korean police have tentatively concluded that convicted murderer Lee Chun-jae, who recently confessed to the decades-old serial killings in Hwaseong, Gyeonggi Province, had committed the eighth murder in the case, which had been labeled a copycat crime.

Authorities revealed in a press briefing Friday that the confession given by the 56-year-old fit most of the evidence recorded from the crime scene back in 1988.

Lee, who is currently in prison for murdering his sister-in-law, belatedly confessed to killing the ten Hwaseong murder victims amid fresh evidence, including DNA analysis, that linked him to some of the crime scenes.

The eighth victim in the string of murders was a 13-year-old girl who was raped and killed in her home. Police at the time arrested a 22-year-old mechanic, surnamed Yoon, concluding he was a copycat killer.

The young man was sentenced to life in prison in 1989 and served nearly 20 years behind bars despite arguing in court that he was forced by police to make a false confession. 

In light of Lee's confession, police reopened an investigation to find out whether Lee or Yoon was behind the eighth murder case.