Arthur Patterson / Korea Times file

By Jung Min-ho

The Supreme Court has upheld a 20-year prison sentence for Arthur Patterson, who killed a 22-year-old Korean at a Burger King outlet in Itaewon 20 years ago.

The verdict delivered Wednesday has put an end to the mysterious "Itaewon murder" case, in which two suspects were investigated for the death of Cho Joong-pil in a Burger King bathroom.

The top court upheld the Seoul High Court's ruling on a lower court that sentenced the son of a U.S. military contractor to 20 years in prison for stabbing the college student to death in 1997 with no clear motive.

A panel of judges presided over by Kim Jae-hyung said in a statement there was no doubt that Patterson was the murderer and he deserved the punishment.

Lee Bok-soo, the victim's mother, appreciated Hong Ki-seon, the director of the 2009 movie "The Case of the Itaewon Homicide" which depicted the case, and the media for their attention that led to the long-awaited verdict.

"My son was a good man," she told reporters after the verdict. "Justice was served thanks to the great public attention to the case."

A 20-year prison sentence is the maximum term for suspects aged 18 or younger at the time of the murder. Patterson was 17 years old when he stabbed the Korean man's neck and torso nine times. Prosecutors concluded that he did so only to "show off" to his friend.

Patterson was able to avoid punishment for so long because prosecutors failed to identify the right suspect in their initial investigation. They wrongly pressed murder charges against Edward Lee, another U.S. dependent who was present at the crime scene.

It was a difficult case for prosecutors because neither Patterson nor Lee had any reason to kill Cho, who had never met them before that night.

Initially, prosecutors indicted Patterson only for possessing an illegal weapon and destroying evidence, and he was sentenced to 18 months in prison in 1997.

When Lee was acquitted due to lack of evidence in 1999, prosecutors came under criticism for the "murder case without a murderer."

Prosecutors belatedly reopened the case to indict Patterson as a prime murder suspect. But by then, he had returned to California after serving his prison term. He was able to leave Korea because the prosecution forgot to renew a travel ban on him.

In 2006, a Seoul court ordered the government to pay 34 million won in compensation to the victim's family because prosecutors failed to do their job properly.

This could have been the end of the story. But for the film that was released in 2009 to pressure the prosecution to reopen their investigation.