They find K’s weapon—a specific type of knife—and track his stolen vehicle.
At the trial, K almost walks free due to a lack of physical evidence. In a final masterstroke, Dong-soo turns himself in to the police. Since he is the only survivor of K's attacks, his testimony is the "smoking gun." The Gangster, The Cop, The Devil
K is sentenced to death and sent to prison. In the final scene, Dong-soo is sent to the same prison. As he enters the showers where K is hiding, Dong-soo smiles and says, "I told you there are three men who will risk their lives to catch you." If you'd like to dive deeper into this world: of the characters' moral gray areas Comparisons to the real-life "Cheonan serial killer" case They find K’s weapon—a specific type of knife—and