The first one used "The Past Can Only Be Recalled" and the second one used "Pink Memories".
The "Chinatown Detective" movie series is one of the hot movies, and both Chinatown Detective films are well-conceived and tightly plotted, making them rare masterpieces.
Both use decades-old songs as interludes.
Extended information:
In both movies the interludes were sung by the Taiwanese Chinese singer "Han Po-Yi "