The Case of the Gilded Lily, by Erle Stanley Gardner
The 'Foreword' dedicates this book to Walter J. R. Camp, M.D., Ph.D., one of this country's leading toxicologists. He is a Professor of Toxicology and Pharmacology at the University of Illinois, and the Coroner's Toxicologist for Cook County (Chicago). Dr. Camp is cool and objective when working on many spectacular cases.
Stewart G. Bedford is a wealthy business man who recently married a much younger woman. Binney Denham visited him one morning and asked about a "loan"; Binney has police records of Stewart's new wife Ann! Bedford loves his trophy wife and enjoys the envy and admiration of his friends. Then a phone call that night insists on getting the money next morning. Bedford gets traveler's cheques, then visits Binney and drives away with Geraldine Corning to a motel as part of the pay-off. A drink causes Bedford to fall asleep, as if it was drugged. When Bedford wakes up he finds Corning gone, and Binney shot dead in the next room. Bedford's secretary drives there and picks him up, she has retained Perry Mason.
Perry gets the story from Bedford and his secretary Elsa Griffin, and advises them what to do. Paul Drake begins his investigation. Elsa will return to her motel unit to lift any of the fingerprints left there by an unknown visitor (Chapter 6). The motel manager accurately described the man and the girl he was with: "that indefinable something that marks the babe, the chick, the moll" [body language?]. Perry finds out who the unknown visitor was (Chapter 8). But that person denied being there, and admits to other actions (Chapter 9). Mason is called, but the police reach Bedford first. Against Mason's advice Bedford makes a statement; the police take him in (Chapter 13). Mason talks to Bedford in jail, and listens to Bedford's theory of the crime (Chapter 15).
The shadow on Grace Corning reports she is leaving for Mexico under a disguise. Drake's operatives get fingerprints from Grace Compton's apartment (Chapter 17). The trial starts in Chapter 18. The motel manager testifies, and we learn new facts about the events (he saw Binney visit, and a "prowler" that he described to the police). A police officer tells of searching the garage to find a hidden gun. Elsa Griffin visits Perry to tell him of her suspicions; as she leaves she meets Sgt. Holcomb and offers her information (Chapter 19). When the trial resumes Elsa Griffin testifies about the fingerprints she lifted; but they do not match the People's Exhibits! Something wrong here. The police fingerprint expert is called to settle this dispute. Then the motel manager takes the witness stand to identify Mrs. Bedford! But Perry asks a few questions that expose new facts (Chapter 20). Perry explains the events to his freed client (Chapter 21).
In other novels Gardner warned about an eyewitness whose testimony can't be corroborated. The fact of substituted fingerprints is subtly mentioned here. Gardner covered the Sir Harry Oakes murder trial for the Hearst Press.