Cruel & Unusual by Patricia Cornwell (Kay Scarpetta #4)

Virginia Chief Medical Examiner Kay Scarpetta is called in to autopsy the body of convicted murderer Ronnie Waddell after his execution. Several days after the execution, a young boy is discovered murdered in the fashion of Waddell's earlier killings, with Waddell's prints near the body. Scarpetta, along with FBI Agent Benton Wesley and Detective Pete Marino, try to discover how a dead inmate could have possibly committed another murder after his death. As the story progresses she seeks the assistance of her 17-year-old niece Lucy after she discovers a strange folder on her computer.