The Black Swan Mystery

Early one morning, a body is found lying next to the railway tracks just outside of Kuki Station in Saitama Prefecture, shot dead. It is identified as belonging to the owner of a local mill which is embroiled in a labour dispute. Suspicion initially falls on the workers' union, then on a new religious sect that has been gaining followers recently.
Chief Inspector Onitsura and his assistant Tanna are called in to investigate, and soon set off in a journey across Japan, from Tokyo to Kyoto and Osaka, and finally to the island of Kyūshu, in a hunt for the killer.
But as they investigate, the killer strikes again, and again. Will they be able to catch the murderer before even more people are slain?