Mad Detective

Lau Ching-Wan

Inspector Chan Kwai Bun

Andy On Chi-Kit

Inspector Ho Ka-on

Gordon Lam Ka-Tung

Ko Chi Wai

Kelly Lin Hsi-Lei

May Cheung

Karen Lee Choi-Ling

Gigi

Joseph Lee Kwok-Lun

Wong Kwok Chu

Eddie Cheung Siu-Fai

Violent Man - Ko's Inner Personality

Lam Suet

Fatso - Ko's Inner Personality

Jay Lau Kam-Ling

Calculating Woman - Ko's Inner Personality

Jeff Cheung Ka-Kit

Ko's Inner Personality

Lu Ching-Ting

Ko's Inner Personality

Chiu Chi-Shing

Ko's Inner Personality

Hung Wai-Leung

Ko's Inner Personality

Flora Chan Wai-Shan

May Cheung in Bun's Eyes

Jonathan Lee Yat-Sing

Weak Boy - Ho's Inner Personality

Jo Kok Cho-Lam

Schemy Woman - Ho's Inner Personality

Eddy Ko Hung

The Chief

Yuen Ling-To

Policeman

Jimmy Wong

Restaurant Manager

Ronald Yan Mau-Keung

Chi-Wai's Boss

Apple Chow Suk-Wai

7-11 Worker

Jackson Ha Chak-Shun

Ko's Colleague

Jack Lai Jan-Lung

Ko's Colleague

Singh Hartihan Bitto

Naresh Sharma

Wong Shiu-Keung

Policeman (uncredited)

Lui Siu-Ming

Mahjong Parlour's Staff (uncredited)

Mark Cheung Yiu-Fai

Mahjong Parlour Customer (uncredited)

Soi Cheang

Inspector Ho Ka-on (voice)

Florence Kwok Siu-Wan

May Cheung (voice)

Peter Chan Bei-Dak

Cameo (picture in police file)

Johnnie To

Director

Wai Ka-Fai

Director

Wai Ka-Fai

Screenplay

Au Kin-Yee

Screenplay

Chiu Chi-Shing

Unit Manager

Charles Heung

Executive Producer

Kuk Kok-Leung

Line Producer

Johnnie To

Producer

Wai Ka-Fai

Producer

Cheng Siu-Keung

Director of Photography

Raymond Chan Kam-Ho

Production Design

Martin Richard Chappell

Sound Designer