This was, in so many ways, such a unique take on a traditional thriller that I'm still wrapping my head around what Beukes did here. To be specific, she created a unique take on a serial killer thriller. Just to boggle your mind some more.
First and foremost, Beukes is from South Africa. She is not from Chicago. This will surprise you because of how detailed and spot-on she crafts her fictional Chicagos. Yes, multiple Chicagos because this has time travel - of a sort - in it. Some folks have trouble with time travel in novels that aren't technically science fiction, so I'm noting that in case it matters to you!
The chapters in her novel are split between the point of view of the serial killer in question and each of his victims. You might find it a bit difficult to keep up with when our killer has gone to specific points in the timeline of his victims' lives, but even when I was a bit lost, I didn't mind. Beukes makes up for that with her descriptions of the milieu of each victim. You immediately get a sense of who they are and their personality, as well as their hopes and dreams. It's almost unbelievably well crafted (the "dog in the woods" scene with our main protagonist / victim was one of the most eerily evocative scenes I've read in a long while).
Also, if you feel... weird while you're reading this, give it some time. I was quite creeped out at the beginning, but the novel grew on my pretty fast (likely about 40 pages in).