Mad Detective

Lau Ching-Wan

As Inspector Chan Kwai Bun

Andy On Chi-Kit

As Inspector Ho Ka-on

Gordon Lam Ka-Tung

As Ko Chi Wai

Kelly Lin Hsi-Lei

As May Cheung

Karen Lee Choi-Ling

As Gigi

Joseph Lee Kwok-Lun

As Wong Kwok Chu

Eddie Cheung Siu-Fai

As Violent Man - Ko's Inner Personality

Lam Suet

As Fatso - Ko's Inner Personality

Jay Lau Kam-Ling

As Calculating Woman - Ko's Inner Personality

Jeff Cheung Ka-Kit

As Ko's Inner Personality

Lu Ching-Ting

As Ko's Inner Personality

Chiu Chi-Shing

As Ko's Inner Personality

Hung Wai-Leung

As Ko's Inner Personality

Flora Chan Wai-Shan

As May Cheung in Bun's Eyes

Jonathan Lee Yat-Sing

As Weak Boy - Ho's Inner Personality

Jo Kok Cho-Lam

As Schemy Woman - Ho's Inner Personality

Eddy Ko Hung

As The Chief

Yuen Ling-To

As Policeman

Jimmy Wong

As Restaurant Manager

Ronald Yan Mau-Keung

As Chi-Wai's Boss

Apple Chow Suk-Wai

As 7-11 Worker

Jackson Ha Chak-Shun

As Ko's Colleague

Jack Lai Jan-Lung

As Ko's Colleague

Singh Hartihan Bitto

As Naresh Sharma

Wong Shiu-Keung

As Policeman (uncredited)

Lui Siu-Ming

As Mahjong Parlour's Staff (uncredited)

Mark Cheung Yiu-Fai

As Mahjong Parlour Customer (uncredited)

Soi Cheang

As Inspector Ho Ka-on (voice)

Florence Kwok Siu-Wan

As May Cheung (voice)

Peter Chan Bei-Dak

As Cameo (picture in police file)