The Devil's Star by Jo Nesbo

Still suffering from alcohol-fueled demons and obsessed with hunting for evidence against a clearly dirty cop, Hole grudgingly agrees to help look into the murder of a woman whose finger has been amputated and a red diamond stuck under her eyelid. More bodies follow, with the murderer leaving identical five-pointed diamonds (the titular devil's star) at each crime scene. At first the killings appear to be random, but Hole soon discovers an ominous pattern.  

Lots of twists and turns. Harry is his own worst enemy at times. 

Archangel's Heart by Nalini Singh

Excellent addition to the series.  Eve and Raphael's relationship continues to grow as they trust each other.  They rescue Eve's grandparents and find out a bit more of her family history.  We are told a few more hints about Aodhan, I am really looking forward to his book.