There were some minor issues with this that I found distracting: Broken or improperly placed quotation marks, you not your, omitted words, etc. It could use an edit to really polish it, and smooth out the pacing in the beginning. At first, I didn't get into it, because the beginning happened so quickly, and the manner in which the characterization and backstory is presented does not feel organic.
There's lots of gruesome details, and obviously a lot of research that went into it, and it was a fun read, aside from the issues in the first paragraph. Very, very dark crime fiction, and if that's your thing, you'll enjoy it. I enjoyed it a lot, once I got past the beginning, though there were a few events in the latter portion of it that didn't make sense to me, or that characters didn't seem to react to properly.