The House with the Blue Door — Hulbert Footner

Sandra Cassells, a rich widow, has set up a home for ex-convicts, but her good intentions create a boiling cauldron of trouble, as passion, jealousy, and manipulation lead to murder. Amos Lee Mappin has no difficulty finding suspects and motives-and it quickly becomes obvious that no one is outside the scope of his investigation. But can he find the killer before more bodies show up? The House with the Blue Door was first published in 1942.