If you are looking for a gritty thriller that combines elements of real-world crime with stylized action, The Gangster, The Cop, The Devil is a fantastic choice, even if it dramatizes the "true story" for maximum cinematic impact. If you'd like, I can:

Given the gritty realism of Korean cinema (think Memories of Murder or The Chaser ), it is a natural instinct to ask if this shocking narrative was ripped from the headlines. The short answer is

They eventually shook hands. The gangster used his illegal gambling dens and loan offices as intelligence hubs, gathering reports of similar "random traffic attacks." The detective fed this information into the official police database. Within six months, they triangulated Kang Ho-sung’s pattern and arrested him.