The Devotion of Suspect X by Keigo Higashino

What ensues is a battle of wits based around a mathematical philosophical question: what is harder – devising an unsolvable problem or solving that problem and knowing if it is correct? A cat and mouse game evolves, with Ishigami tweaking his plan in light of unfolding events. The second is Ishigami’s former university friend, Manabu Yukawa, a physicist who occasionally helps the police. The first is Yashuko, who takes up with an old flame in the days following the murder. There are two unaccounted element in Ishigami’s machinations. The unfolding story then revolves around the police probing the alibi and trying to trace Togashi’s last movements, with the mystery essentially being whether they’ll be able to get to the truth given Ishigami’s carefully plotted cover-up.

It appears though that she has a verifiable alibi for the time of the murder and she’s sticking to pleading ignorance. A body is subsequently found, quickly identified and the police turn up at Yashuko’s door. Their neighbour, Ishigami, who is smitten with Yusuko, hears the fight and offers to help them dispose of the body and create a cover-up. Yasuko Hanaoka and her daughter murder her abusive former husband. The reader is presented with the murder at the start of the novel. Set in Tokyo, The Devotion of Suspect X is a police procedural with a difference. He’s somewhat surprised that Ishigami is a high school teacher, but knows that if he is involved in the case that it will be fiendishly difficult to solve.

Yukawa was a friend of Ishigami at university and knows him as a mathematics genius. Detective Kusanagi can find no holes in Yasoko’s alibi, but there is something about the case that un-nerves him and he turns to his friend, Manabu Yukawa, a university physicist, for help. All Yasuko and her daughter need to do is stick to the story Ishigami creates for them when questioned by the police. Hearing the commotion, Ishigami offers to help get rid of the body and to plot the cover-up. The confrontation spirals out of control, ending with mother and daughter killing Togashi. One day her former husband, Togashi, turns up looking for money and threatening continued harassment. A former nightclub hostess she now works in a local takeaway where her neighbour, a high school mathematics teacher, Ishigami buys his lunch each day. Yasuko Hanaoka is a divorced, single mother.

The Devotion of Suspect X by Keigo Higashino