The literal translation of the title of this movie is: The Case of Qiu-Ying Xu.
This movie, like most Chinese crime movie, is based on the true story, which really happened in 1950's. The case was actually a spy case involving the failed nationalist attempt to draft Miss Qiu-Ying Xu as a spy by threatening to expose her past history of being in some anti-communist organizations prior to the revolution. This part, however, was not mentioned in the movie, which only showed the facts that she was murdered after she refused to do so, and the consequent effort to solve her murder and final arrests of nationalists agents.
However, the forgotten historical part in the movie was not forgotten during the political movements that came later in China, namely, the Cultural Revolution. This part of the history was dug up and was used as an excuse to persecute everyone related to this case.