Shenzhen Win's Video Production Service Limited

Involves a psychotic (possibly demonic) female.

Female detective is on the trail of a serial killer raping and murdering busty women, whose victims include the policewoman's sidekick. Along the way, she seeks help from another cunning serial killer called Lam, already in jail. In exchange for Lam's psychological insight into the case, she may have to pay the ultimate price.