A South Korean man, who was imprisoned for 20 years after being wrongfully convicted of raping and killing a 13-year-old girl in 1988, was acquitted of the crime in a retrial on Thursday. The Suwon District Court in Suwon, south of Seoul, overturned the original conviction of Yoon Seong-yeo, a 53-year-old, and declared him not guilty in a retrial of the 1988 murder case linked to one of the nation’s most notorious serial killings. The court offered an apology to Yoon on behalf of the judiciary, saying the incorrect ruling of the past was made due to wrongful acts by investigation agencies. Yoon’s case was classified as the eighth case of 10 serial murders that had occurred between 1986 and 1991 in Hwaseong, a Gyeonggi Province city about 60 kilometers south of Seoul. The case was initially concluded as a copycat crime of the other murder cases in Hwaseong, which had remained an unsolved criminal mystery until recently. In 1989, a district court sentenced Yoon, who was then 22 years old, to a lifetime in prison, convicting him of the 1988 rape-murder case. He had pleaded innocent, claiming the police forced him to confess to a crime he did not commit, but the appeals court and the Supreme Court upheld the lower court ruling, putting him behind bars for 20 years until he was released on parole in 2009.