"Death of a Doxy," by Rex Stout

In Archie Goodwin's world view, the word that best fits Isabel Kerr is a four-letter word: doxy. The dictionary says, it defines "a woman who is regarded as sexually promiscuous." Only trouble was, Isabel Kerr was dead. Murdered. And – with the police focused on a suspect who is both a friend and sometime colleague of both Archie Goodwin and Nero Wolfe, it was clear that  Wolfe was going to have to get involved in the search for the real killer.