At the beginning, because the assassins were talking in Iyo dialect, it was thought that the deed was done by Sanosuke HARADA and Kuwajiro OISHI of the Shinsengumi (a group who guarded Kyoto during the end of Tokugawa Shogunate).
当初、刺客が「こなくそ」と伊予弁を話していたことなどから、新選組の原田左之助や大石鍬次郎らの仕業とされた。