Who Watcheth

"He watches the women from the shadows. He has an understanding with them; as long as they follow his rules, they are safe. But when they sin, he sentences them to death. A woman is found dead in a cemetery, strangled and covered in plastic. A thorough examination of the corpse reveals that the killer left behind no evidence. But just a few days before her death, the victim received a flower, an unintelligible note, and a photograph of herself. Detective Inspector Irene Huss and her colleagues on the Geoteborg police force have neither clue nor motive to trace, and when similar murders follow, their search for the killer becomes increasingly desperate.