What is the ghost film about being a policeman played by Feng Cuifan, an old Hong Kong artist?

The film tells the story of Zhang Biao's investigation into drug making and his tragic death under the gun of a drug dealer. Zhang sneaked back to the police station and found out the murderer through the hand of Officer A Xing. Li Jin and A Xing, under the guidance of the bodhi old zu in Maoshan, defeated the evil mage with elixir, killed Deng Liyang and avenged Zhang Biao, so that he could go to heaven with peace of mind.

Brothers in Ghost is an action, comedy and fantasy film directed by Sze Yu Lau and starring Stephen Chow, Dong Piao, Feng Cuifan, Vivian, Fang Gang, Mei Xiaohui, Ye Zimei, Mai Xinhua and Wang Tianlin. It was released in Hongkong, China on July 28th, 1990.