Lady Cop & Papa Crook (Chinese: 大搜查之女; pinyin: Da sou zha zhi nu; Cantonese Yale: Daai sau cha ji neui) is a 2008 Hong Kong crime film written and directed by Alan Mak and Felix Chong, and starring Sammi Cheng and Eason Chan.

When an oil tanker explodes accidentally, he becomes the focus of investigation by Hong Kong and Mainland Chinese police and is forced to halt his business to wait things out.

Senior Inspector Maureen Szeto (Sammi Cheng) is the rising star in the police force, who is well praised for busting crime with her characteristic sangfroid and precision.

Lady Cop & Papa Crook marks the second co-directorial partnership between Alan Mak and Felix Chong, the writers behind the Infernal Affairs trilogy.

Chong and Mak decided that the film would center on a female police officer, and immediately thought of Sammi Cheng being cast in the lead role.

[5] Lady Cop & Papa Crook was scheduled for released in September 2008, but was postponed when the film failed to meet Chinese government censorship standards.

Lady Cop & Papa Crook was submitted to the Hong Kong government's Television and Entertainment Licensing Authority on 7 August 2008, with a version running at 97 minutes.