Van Dine, S.S.: Vance 03 - The Greene Murder Case. v1. 10 Sep 07
The third book in the "Philo Vance" series.
The members of a wealthy New York family, living in an old walled mansion, are being picked off, one by one. Philo Vance investigates...
As a side-note, in this book Van Dine solves the problem of how a certain, seemingly impossible, crime, could be committed in exactly the same way as in one of the later "Sherlock Holmes" stories. I don't know if he got it from Conan Doyle, or if both got it from the same original source (which is quoted in this book as a footnote). Anyway, an interesting coincidence. I won't say any more because it would be a "spoiler" - send me a PM if you want details!