The Skeleton Road by Val McDermid

When the bones of a man are found hidden away in a building about to be torn down in Edinburgh, DCI Karen Pirie--as head of the Historic Case Unit--is put in charge. With help from a friend who's a forensic anthropologist, they are able to determine that the person died between five and ten years ago. In Oxford, professor Maggie Blake still misses her boyfriend, Dimitar Petrovic, who left her eight years ago--which was about the time someone started carrying out vigilante justice by murdering Serbian men involved in atrocities during the Balkan War. Is Petrovic, a Croatian, the one who's been avenging the violence against his people or was it his skeleton up of the roof of the old building? In this mystery, Val McDermid brings back detective Karen Pirie from her book, A Darker Domain, to explore and unravel the mystery of Dimitar Petrovic's life.