Trace by Patricia Cornwell

Trace is a 2004 crime novel by Patricia Cornwell, the 13th book in the Kay Scarpetta series, where the protagonist returns to Virginia as a consultant to investigate the murder of a teenage girl, uncovering a link to a larger conspiracy that threatens those closest to her. The story follows Scarpetta as she navigates a changed professional landscape and uses forensic evidence to prove the murder, finding connections to other cases involving her niece Lucy and Pete Marino.