This is a lousy attempt of Chinese film crew in the new era trying to mix crime, thriller and mystery with docudrama.
The story is based on the real thing, most of which are reflected honestly in this movie, but to emphasize the thrilling/mysterious effect, the random serial killing in real life is changed to a regular occurrence on April 30. This exaggeration did not help in increasing the thrilling and mysterious effect, but instead, tarnished the entire picture. Perhaps just making a pure crime docudrama was better.