To be able to dive into the mindset of a serial murderer (or at least a part of it) was super interesting. However, I knocked off a star because as much as I can sympathize with Jazz, with his consistent mantra of how he feels like he'll turn into a serial killer - or his constant nag that he has to do certain things to not become like his dad got a bit annoying. 
 I don't want to delve too deep because murder mysteries like these are best left with as little knowledge as possible. 
 That aside, I figured out who the murderer was from the moment I read the name. I think I watch too many dramas that involved crime scenes so not the fault of the author.