The Accomplice by Matthew Head Dell Publishing, 1947, 240 pages

Hank Bewley has a crush on Corrie Walters, who in turn is in love with Lex Abbott, who accidentally married the uber-odd Mimi Decors.
Hank serves as the narrator. His voice submerges itself in the story. Despite the long sentences, it never overstays its welcome.
“I was at a bar, in Paris. Not a fancy bar, and not a student bar, just a nice commonplace comfortable little bar, and we were drinking chocolate. This was in the middle nineteen-thirties, 1934 to be exact, and I was with a very nice girl from Kansas City, named Corrie Walters.
…She didn’t have the kind of ravishing good looks that take you off your feet at first glance, or even the impertinent prettiness that can hit just as hard, but the longer you looked at her, the more nice things you began to discover.”
Mimi is the one on the cover and readers can correctly assume she’s the one who dies. The murder takes place late in the story. It becomes incidental to the intertwining lives of the characters.
This would all be mundane treachery, but Mimi believes she is the reincarnation of Ninon de Lenclos. She also runs a cult called Kwanah, where people find their famous personalities through history. Mimi manipulatively uses her wily powers to bind herself to Lex.

Of course, Lex is a rich, pretty boy with a violent streak. Hank has his eye on Corrie, who can’t seem to let go of her crush on Lex. Try as he might, Hank can’t get Corrie to forget Lex. Both she and Mimi are possessed by him.
The death itself adds a surprising element to the book. I would’ve thought that having sex with a corpse would be unmentionable in 1947.
There’s a list of characters in the beginning of the book, along with a map of Mimi Décors’ house on the back cover. The uncredited cover art is fabulous, and was recently duplicated. (Or do we call that an homage?)
A solid psychological thriller which definitely stands the test of time.