from the back of the book:
Handsome Mark Callender did not die the way a well-brought-up gentleman should. He was found hanging by his neck, a lipstick stain on his mouth and a picture of a nude girl nearby. The official verdict was suicide, but his aristocratic father suspected murder, and hired fledgling detective Cordelia Gray to investigate. As this determined young lady followed a twisting trail of guilty secrets and shameful sins, she soon reached the conclusion that the nicest people do the nastiest things — in a case that proves at every shocking turn to be "An Unsuitable Job for a Woman."
That's not quite right, though, because the picture of the nude isn't found until later, and at no point is there the suggestion that Mark Callender's father "suspected murder". Sometimes the text on the backs of books is not what you'd call accurate... Or maybe I'm just in a picky mood.