This was an enjoyable detective story/thriller with a few extra elements. The main 'extra' was that the reader gets to learn (or at least read, if your memory is like mine) a whole load of Maori words and also some customs. That made it more interesting and added some depth, as did the issue of racism.
The book was easy to read and after a while turned into a real page turner; I really wanted to know what happened next.
There were a couple of less good points, at least in my opinion. How likely is it that someone would accidentally come across someone's search history? Why didn't the divers use drysuits (which are much warmer)? The incident with the magpie was a little too predictable.  What was the point of the first arrest? 
Nevertheless,  those were minor points and I enjoyed reading the book. 
This book was kindly provided by the publisher via NetGalley in return for an honest review.