Release Date: October 1st, 1999
Page number: 190 pages
This is a novel, written by Naoko Korekata, which takes place in the Silver Case setting, between the fourth and the fifth case. Specifically, it follows Sakura Natsume while she investigates a series of murders during her time as a police traineé.
The novel has been fully translated, and you can read it here:
(HERE‘s an archive link in case it ever goes offline.)