Comeuppance (2000)

Michael is a cop chasing uncommon serial killer Sung Ping, who one day kills off a scummy triad on almost a whim. Liking the aftermath, he proceeds to plan his next few killings much to the dismay of the local triads. Meanwhile, reporter Hak makes the real-life crime drama the fodder for his crime fiction serial. Before long, Ping begins using the fiction to fuel his own plans, and soon Hak is concerned that he may be responsible.