"Killing Cousins" is a 1960 mystery novel by Fletcher Flora, a writer who wrote many novels and short stories in the mystery genre. It was published as one-half of an Ace Double, with the other side being The Blonde Cried Murder by John Creighton.
I am not as familiar with mystery tropes as I am with science-fiction, and in this, my first Ace Mystery double, I was happily surprised to see how different the stories were. While "The Blonde Cried Murder" was a predictable but good hard boiled story, "Killing Cousins" was something quite different, and not really a mystery at all. It is something of a police procedural, but from the criminal's point of view. It also has much more social satire, bordering on a type of black comedy. It follows Willie Hogan, a suburban housewife of a man named Howard Hogan. Willie is bored and neglected, and is flirtatious and adulterous with several men, including her husband's cousin, Quincy. When her husband confronts her about her behavior, she "accidentally" shoots him, and calls Quincy to hide the body. They are amateurs out to hide a body and cover-up a crime, and the only reason they succeed is that nobody in their small town is very quick-witted. Quincy is a wannabe operator whose major resource is a cousin who is a small-time hood. Willie's major advantage is that she is seductively beautiful, in a neglected housewife sort of way. The plan they have isn't very good, even for a time before modern forensic investigation technology, but it works quite well to show the decadence of country-club suburbia, with the constant stream of martinis and affairs. And while it could be argued, even in 1960, that this wasn't a novel point, the book still paints its satire with sharp details. And, in a way, a type of sensuality and scandal that was probably shocking for the time.
Incidentally, I learned that Fletcher Flora was a writer of "lesbian pulp", and that he was one of the few writers who did it under their own name. I certainly detected strains of that in this book, such as where Willie, a neglected housewife, turns to her neighbor Gwen, also a neglected housewife, for companionship. It was not clear to me whether some of the social criticism in this book was advocacy for different or more open lifestyles, or whether it was just to titillate the reader.
After reading this first volume of vintange mystery and crime fiction, I realize the genre was broader than I thought, and am interested in reading more.