Black Mail — Doris Miles Disney

Who would want to persecute a girl like Lucia Ruyter? At the bank her warm friendliness and easy efficiency made her a pleasure to work with; her neighbors all spoke of her with affection, and the men in her life knew her to be a delightful and attractive young woman.

But Lucia had suddenly become the subject of a series of pointedly obscene, anonymous letters. And it was only a matter of time before Postal Inspector David Madden realized that although he could save Lucia's reputation he might not be able to save her life.