『人間豹』is the 8th book in the Kogoro Akechi collection published by Shueisha.
I enjoyed this novel very much, but it is not as good as 『吸血鬼』or 『魔術師』in my opinion. Most novels of the series have very similar structures and differ mainly by their bad guy, who becomes the main attraction of the story. To make the criminals more and more appealing, Edogawa Rampo often uses features that are close to being supernatural, and the physical appearance of the characters also gives their dimension of horror to the novels.
We find all of these here with the “human-leopard”:
There is an emphasis on the physical appearance and physical features of this character, and this novel is mainly the confrontation 殺人鬼 vs 名探偵. The novel is a succession of duels between Akechi and the 人間豹 with each character trying to trap the other. The winner is the one who uses the more tricks and is able to see through the other’s plan. We even see them congratulating each other on the phone for their good tricks.
It was nice to read, but I personally prefer reading a story with a linear plot rather than a succession of tricks, traps and escapes. Furthermore, there was no motive of any sort in this novel (contrary to the previous one), and we are back to a story where the criminal kills people because he is a bad guy.
Furthermore, the mystery behind the existence of the man-leopard is not explained in the novel. I think that even a pseudo scientific explanation could have been nice, but the novel does not provide any.
This being said, it is still enjoyable to follow the adventures of Kogoro Akechi, even more so as we meet the characters of Fumiyo and Kobayashi again, who brings a lot to the series.