Ashes to Dust by Yrsa Sigurdardottir

Lawyer Thora Gudmundsdottir is with her client, Markus Magnusson, as he goes into the basement of his childhood home in the Westmann Islands off the southern coast of Iceland. The house was abandoned in 1973, when a volcano erupted in the area. Magnus is there now to retrieve a box for his friend, Alda. He gets the shock of his life when a head rolls out of the box. Next to the box, he discovers the remains of three men. Suspicion immediately falls on Markus and things get worse for him when Alda is found dead in her home. Thora immerses herself in Markus' past, specifically the time around the volcanic eruption in an attempt to prove her client's innocence. Ashes to Dust is the third book in the Thora Gudmundsdottir series, but has not been published in the U.S. The mysteries are similar to Asa Larsson and Helene Tursten.