I have been trying to remember the name of a book I likely read in the early 1990s but could have been published much earlier than that. Every time I describe it to someone they guess it’s The Westing Game, but it is not.
A girl is invited to her aunt’s house for a visit. The aunt is married to a prominent and rich man (possibly a journalist? He is someone the girl is aware of and admires) who is throwing a party at his estate for a large number of famous friends. Once the guests are assembled it’s revealed via clues that the man has knowledge of something unsavory from each of their pasts (including his wife’s) and is blackmailing them.
That night the man is murdered and the book becomes an Agatha Christie style whodunit, knowing that the murderer must be one of the people in the house. The girl is able to learn about all of the guests and eventually solves the murder – the killer is a loyal housekeeper who doesn’t want the aunt’s secret to get out.
My son is now approaching the age I was when I read the book (probably 10 or 11?) and I’d love to find it for him since he enjoys mysteries but I cannot for the life of me remember the title, nor track it down with any kind of “books similar to the Westing Game” style searches.