Nude Fear

Joyce Chan Ching Yee, a 28-year-old superintendent of the Homicide Bureau. While investigating a horrific rape-murder, she immediately recognises the killer's modus operandi — it's the same one used by the man who murdered her mother 23 years before. Chan's investigation leads to the capture of Lee Chun Min, who confesses to the murder of Chan's mother and several other women. Lee was arrested years before but was released without a trial. As Lee is only 23, Chan is convinced an older serial killer is still on the loose, but the investigation comes to an abrupt halt when Lee kills himself.
A confused young girl, whom psychiatrists believe has been imprisoned, is unable to tell anyone who she is. However, she has a photo of Chan, who doesn't recognise her. Chan receives a phone call from the girl's captor and realises he has intentionally released the girl. The serial killer then arrives at Chan's apartment, kills three detectives, and captures and taunts Chan but does not kill her. Despite not having seen his face, Chan is convinced from the encounter he works in the police department. Soon, Officer Cheung Chi Chuen is arrested, and the girl identifies him in a lineup. Before trial, Cheung is stabbed to death by the father of one of the victims.
The case is now closed, and the girl, having been identified as Cheung Sze Mei, reunites with her parents, who lost her 12 years ago. Officer Wong Wing Nin of the Public Relations Bureau arrives at Chan's apartment to celebrate. Chan and Wong make love after a few drinks. While Wong is in the shower, Chan accidentally picks up his phone and hears the voice of "Cheung Sze Mei". At the same time, Chan's assistant discovers it was Wong who, many years ago, secured Lee's release, and realizes that Wong is the killer.