Bad for Business
Rex Stout
 Amy Duncan is a private investigator for the firm of Bonner and Raffray (see The Hand in the Glove for more complete information about Dol Bonner and this company) and the youngest of four women on what is called the "siren squad". Her detective work is based on the theory that most men get careless eventually around pretty women, especially those with chartreuse eyes like hers, and she's been trying to encourage a handsome young man named Leonard Cliff to get careless when she gets knocked down (harmlessly) by a car driven by private investigator Tecumseh Fox. He learns of her assignment, which is to investigate the possibility the company of which Cliff is a vice-president, a large food conglomerate, has been putting quinine into jars of food sold by her uncle's company, Tingley's Tidbits; someone certainly has, and it's bad for business. After a further series of coincidences involving her boss, Cliff and Fox, she is fired and goes to visit her uncle after working hours—she finds him murdered in his office and is promptly knocked unconscious without seeing her assailant. Fox and the police both investigate the company, including its sales manager Sol Fry and production manager G. (for Gwendolyn) Yates, but reserve their suspicions for Tingley's son Phil, who has crackpot ideas about reforming the economic system, and Guthrie Judd, who owns the food conglomerate. Since the quinine problems began, Mr. Tingley has been taking samples from the production line, and the latest sample jar is missing, but so are some documents that relate to the personal lives of Phil Tingley and Guthrie Judd. Fox tracks down the documents and learns Judd's secret, but it brings him no closer to the identity of the murderer. The only thing that does so is remembering a chance remark made by one of the suspects that leads directly to the missing sample jar and the guilty party.