This is a strightforward plice procedural and really stands or falls by both the charachter of the leads and the way they manage the investigation. K.O.Dahl sidesteps the frequent genre cliches and delivers both lead detectives who are competent and interesting without being unduly morose, dysfunctional or at odds with their organisation. Instead they are careful and given lives outside of their work that feel natural and revealing. Both are committed to their task and act carefully to complete the investigation in a way that would bring sustainable solution.
The supporting cast are given the time, space and energy to make an impression so that they can credibly complicate and muddy the investigation. In particular the Peeping Tom neighbor of Reidun is brought to vigorous, grubby life and manages to be deeply unsympathetic without every being annoying. The way that the narrative shifts the possibilities and motives for the murders is very well done, with the real dynamic of the story emerging in an engaging and unexpected way. There is no cheating in the book with abrupt plot shifts being forced on the reader to get to the desired conclusion, the pressure that drives the plot is woven very successfully into the fabric of the story.
One of the pleasures of the story is the recognition that murder is a significant act and this infuses the investigation with a force and depth that can be lost sometimes in the excitement of the hunt.