The Devotion of Suspect X

Yasuko Hanaoka, a divorced single mother who works at a bento shop in Tokyo, thought she had left her abusive ex-husband behind. When he turns up again and a death follows, her neighbor Tetsuya Ishigami, a gifted high school mathematics teacher who is quietly devoted to her, offers a plan to hide what happened.

Detective Shunpei Kusanagi does not believe Yasuko's alibi, but the case refuses to give way. He asks his old college friend, the physicist Manabu Yukawa, whom the police call Galileo, to take a look. Yukawa turns out to know Ishigami from university, and the investigation becomes a duel between two exceptional minds.

First published in Japan in 2005, The Devotion of Suspect X won the 134th Naoki Prize and the Honkaku Mystery Award, and reached English readers in 2011 in Alexander O. Smith's translation. It is an inverted mystery that cares less about who did it than about how the truth is hidden and what that costs.