Gustawsson’s third in her award-winning Roy and Castells series, Blood Song, ties in events of the heinous acts during the brutal dictatorship of Franco’s regime with a series of murders in Falkenberg, Sweden, during contemporary times.

If this seems an unlikely connection, it will be clarified as readers become involved with Scotland Yard’s newest profiler. Alienor Lindbergh’s family have died under especially horrific circumstances, murdered in the wealthy family’s Swedish home.

With her profiler mentor, Canadian Emily Roy, accompanying Alienor home for the investigation, and French true-crime writer Alexis Castells involved, the unlikely trio will soon find that there is a tie to fertility clinics as well as to the sad and terrifying brutality of the orphanages of Franco’s Spain.

As the body count continues to rise, the women use the Swedish police resources as well as their own knowledge to figure out what’s been happening. There will be side trips and tough interviews as the darkness that happened decades ago deeply shadows modern times.

Gustawsson’s Authors Note bears reading first to ground the reader in the research and reasoning in connecting the two time periods. It’s a dark and unpredictable story, with an ending that is extraordinary.