The story had potential, but the introduction of Shusuke fucked everything up.
I'm not necessarily against EVERYONE having issues, but that guy even came out of nowhere with, apparently, the worst issues of them all. It's just too much.
Stretching the story with such sudden and weird twists is not a good thing, it only turns the whole story into heavily scripted garbage.
And while I understand that murder is traumatic and that it's unsettling to have a murderer around, people's actual reactions in this novel to the man who killed the rapist of his sister who committed suicide is... weird? They focus too much on the murder aspect alone, it's hardly believable that way like many other people pointed out in the comments.
This story is far from perfect.