Arthur Patterson was sentenced to 20 years in jail Friday for a stabbing incident that resulted in the death of a South Korean student in a Burger King bathroom in Seoul in 1997.

Thirty-six-year-old Patterson contested to the allegation before, insisting that the victim, Cho Joong-pil, was killed by Edward Lee, a Korean-American accomplice, but Lee insists that Patterson is guilty. Lee was already convicted to life for the murder in 1998, but the decision was reversed because there was not enough evidence.

Judge Shim Gyu-hong noted that the Burger King bathroom was too small for two people to alternately stab the victim. 

"Given the small size of the bathroom, it is highly unlikely that the two could have switched sides to take turns stabbing. With the two constantly accusing each other, it is obvious that one of the two is lying," Gyu-hong said, according to The Korea Times.

"While Lee only had a small amount of blood on his head and shirt, Patterson's head and clothes were covered with a large amount of blood that he was unlikely to have gotten elsewhere," the judge added.

The university student victim Joong-pil was stabbed nine times in a short period of time, which means that there was a huge amount of blood loss. 

Patterson has been claiming innocence even until he was brought back to South Korea from Los Angeles in 2015. 

"There is credibility in statements made by Edward Lee, an accomplice, that (he) witnessed Patterson stabbing the victim," the Seoul Central District Court stated, USA Today reported.

"(Lee) incited Patterson to murder (Cho) and led the way into the bathroom (where the incident took place)."

Patterson lived in Seoul because his father used to be a contractor for the U.S. military. The Burger King where the incident happened is located in Itaewon, which is near a U.S. base, according to BBC News.