A Rather Dastardly Death by Anthony Slayton
A Rather Dastardly Death is the second of the Mr. Quayle Mysteries and the Lord Unsworth and his family are on vacation in the French Riviera, trying to get some distance from the events of A Quite Deadly Affair. Of course, it's not long until someone is murdered, a woman Lord Unsworth knew decades earlier, and the family gets caught up in another investigation. Mr. Quayle, at Lord Unsworth's request, agrees to assist in solving the mystery and protecting the family's reputation if possible.
This is a fun old-fashioned murder mystery with plenty of suspects and possible motives. The dead woman, Lady Rosaline Barrett De Marchi, Widow of Treville-Sur-Mer, was surrounded by "admirers" and hangers-on, any of whom could have killed her. We also have a side plot regarding a jewel thief who may be in the Riviera and a statuette from Lady Rosaline's collection is missing.
All of the characters are notable, but Quayle is what makes this series work...