Roseanna
Per Wahlöö
 A young woman is found dead in a canal, molested and murdered. The case is almost instantly cold: nobody can identify her and where and by whom she was killed. Then a stroke of luck: through Interpol her identity is ascertained—Roseanna McGraw, an American tourist who was taking a boat trip in southern Sweden. A meticulous investigation determines that she was murdered aboard the boat and proceeds to determine if a fellow passenger was responsible.