On a morning in June 1964, an elderly woman was mugged in an alley in San Pedro, California. A white woman with blond hair was seen running from the alley moments later. She got into a yellow car with a white top driven by a black man with a beard and then sped off. The police arrested Janet and Malcolm, a couple who both answered the physical description of the witnesses and owned a yellow Lincoln with a white top. The case seemed destined to become another quickly forgotten mugging case until the prosecutor sought to bolster his circumstantial evidence with mathematical probabilities. At the trial he tried to drive home the unlikelihood of another couple possessing all the same characteristics by calling a mathematician as an expert witness. The expert stated the principle that the likelihood of a number of independent factors occurring...