The Scent(2012)

A detective Seon-woo, who moonlights as a private investigator, has a beautiful new client Soo-Jin. The woman asks the detective to take photos of her husband in the midst of having an affair with another woman. When the detective goes to take pictures he discovers that the woman's husband is already dead. Now the detective becomes a suspect. The detective is chased by another detective Gil-ro. He must now set out for the real killer.