It’s inspired by the true story of Korea’s serial killer panic, but the iconic image of a gangster handcuffed to a cop chasing a devil is pure cinematic genius.
A key part of the true story involves a pimp—not necessarily a "gang boss" in the traditional cinematic sense—who realized his employees were disappearing. This individual began his own investigation and eventually collaborated with the police to lure and capture Yoo in 2004. The Legal Paradox: is the gangster the cop the devil based on true story
This is where the movie leans more into fiction. There is no public record of a high-ranking South Korean mob boss (like Don Lee’s character, Jang Dong-su) survives a serial killer’s attack and then signs a formal "contract" with a police officer to hunt the killer down. It’s inspired by the true story of Korea’s
: Fans and critics often compare the fictional killer "K" to notorious real-life serial killers like Yoo Young-chul (the "Raincoat Killer") and Jeong Nam-gyu . Yoo Young-chul, who was active in the early 2000s and convicted in 2004, remains on death row today—a fact some believe influenced the film's dialogue regarding the finality of the death penalty. The Legal Paradox: This is where the movie
To understand the film’s roots, you have to look at a real person: . He is one of South Korea’s most notorious serial killers, active between September 2003 and July 2004. Known as the "Raincoat Killer" (due to demanding his victims wear a raincoat during the murders) or the "Happy Day" killer (after a message he carved on a victim), Yoo Young-chul confessed to murdering 20 people—mostly wealthy elderly people and female masseuses.