This note contains spoilers for the book.

Client comes in and lies about identity, and gets them involved in a murder.

Guy has a fancy sex pad built into an apartment building he owns. The caretakers have a beautiful daughter—who is smart, and curious, and, it turns out, unscrupulous. She done it, or at least did the blackmailing that set a lot of it in motion.

This old paperback has quite a salacious cover for the time. Which, remarkably, is at least in theory justified by the story. The sex pad has erotic art on the walls, though it isn't described in detail.