I thoroughly enjoyed this book. I loved the killer's internal dialog, I thought it added a really cool and creepy dimension to the whole mystery. (Spoiler Alert...?) I didn't even mind that you don't find out who the killer is at the end of the book.
The characters were well-drawn, for the most part, but I will admit to skipping over a lot of the making of the tiles because I wanted to get back to the main mystery and the relationship of Lia and her detective.