The novel The Devotion of Suspect X is a representative work by Japanese author Keigo Higashino.
 
7:35 PM.
 
Ishigami entered the bento shop. "Welcome!" The voice from behind the counter was already familiar to Ishigami, but every time he heard it, he felt something new. As for Yasuko, Ishigami, her neighbor, was like a crack on the apartment wall—she knew it existed but didn't pay it much attention, and she was certain there was no need to.
 
Starting today, they would share two secrets. One, Ishigami was secretly in love with Yasuko, while Yasuko pretended not to know. Two, Yasuko had caused someone's death, and Ishigami would erase any traces of the deceased ever existing in this world.