Sea Change / Robert B. Parker / 295 pages / Deceased Author Challenge

Police Chief Jesse Stone must investigate when a woman's partially decomposed body washes ashore in Paradise.  Identifying the corpse as Florence Horvath, an attractive recently divorced heiress from Florida is just the beginning.  Jesse's investigations uncover a steamy sex-on-yachts club involving wealthy men, under-aged girls, and video cameras.  Florence was a willing, enthusiastic participant.  If it wasn't someone in the club who caused her death, who did?  Florence's twin sisters, Corliss and Claudia provide invaluable, horrifying information leading to the identity of the killer.