The Invisible Guardian

 This book wasn???t half-bad a ride to be honest. For the most part, it???s about exactly what it says on the tin: a mystery involving a serial killer who???s going around killing young girls. Following that mystery to its conclusion is definitely part of what makes this book an enjoyable read, and there were enough twists that it was hard to predict until the novel???s climax who the serial killer actually was. I???m not going to lie: I didn???t see it coming until just before the reveal, which is a good sign for a mystery, in my opinion. I will say that the killings are quite disturbing, as is the motive behind them - not in the gory sense (though they can get pretty gory too), but in the sense that it makes pretty clear how evil this criminal is, and how twisted their path to perdition. The novel also goes pretty in-depth in describing the crime scenes, as well as the investigative methods used, so those are likely to disturb certain readers. 
Alongside the investigation of the killings, the novel tells the story of Amaia???s family and her surprisingly dark past. Those two storylines - Amaia???s past and the investigation - running in parallel to each other is interesting, mirroring each other in themes of trauma and victimhood, but there were times when the telling of the former would bog down the flow of the latter, or vice-versa. It???s a small gripe for me, personally, but I suspect readers who prefer their mysteries to be more tightly plotted might find these changes in pace annoying. 
The incorporation of the supernatural elements in this story was another thing I enjoyed, but which I think other readers might not. I admit that the way they???re used has a bit of a deus ex machina feel to it, but I tend to see the supernatural elements as more a reflection of Amaia???s worldview, since she did grow up in the Baztan Valley and the myths and legends of the locale would have been deeply ingrained in her subconscious no matter how much distance she tried to put between herself and her past. They also add color to the setting, helping to bring the town of Elizondo and the rest of the Baztan Valley to life. 
Despite all that, a part of me wonders if the rough edges I encountered in the reading are related to the translation, rather than the author???s actual craftsmanship. Would this novel come off as more polished in its original language? Possibly, but I can???t say for certain because I don???t understand Spanish. 
Overall, I found this book enjoyable to read, with an absorbing mystery and interesting characters. The supernatural touches seemed out of place at times, and are likely to rub some readers the wrong way, but other readers will probably find them interesting, lending insight into the setting and the characters. I do wonder, though, if the novel???s rough spots are due to the translation as opposed to the author???s craft, but only readers of the original Spanish will be able to comment on that aspect with any authority.