The wall / Mary Roberts Rinehart.

Enhanced descriptions from Syndetics:

Marcia Lloyd and her brother Arthur have spent every summer of their lives exploring the grand halls and seaside grounds of their family's idyllic vacation home, a gorgeous old mansion called Sunset House built by their grandfather. But when Arthur's ex-wife Juliette arrives at Sunset to demand alimony from him, things take a dark turn and Juliette disappears-her body found a week later. What sordid secrets lie within the creaky old manor? Marcia and the local sheriff Russell Shand must work against the clock to find the murderer in this seemingly utopian upper-class hamlet.

From "the American Agatha Christie" Mary Roberts Rinehart comes a Golden Age murder mystery inspired by her own hauntingly beautiful coastal northeastern home in Bar Harbor; The Wall is both a love letter to quiet waterfront towns as well as a subtle indictment of a wealthy Old New York family attempting to preserve a bourgeois veneer in the shadow of the Great Depression. But beneath all that lies a timeless tale of a family whose conflicts and passions, long masked by efforts toward respectability, finally rise to the surface with violent results.

Originally serialized in The Saturday Evening Post and published in 1938, this classic small-town cozy was among Rinehart's most popular titles in her day; reprinted for the first time in over twenty years, its atmospheric setting and memorable characters continue to distinguish it to this day.

Includes discussion guide questions for use in book clubs.