Quel che rimane - All That Remains, by Patricia Cornwell (1992, USA)

Mark and Kay just split up, she's going on working in Richmond and a new case comes up: the daughter of an important politician is killed. And so her boyfriend. They're found months later. A killer's been killing couples for some years and bodies are found only months later: Kay can find really few over their skeletons. This time sth is different: Pat Harvey (the politician) does all she can to avenge her daughter. Maybe CIA and FBI are involved too, although their role isn't clear. Besides, a journalist, Abby, Kay's friend, plays an unclear role too.
Page turner.