Simon Brown acted as a broker for Kotteakos (defendants) and others in making fraudulent loan applications. Brown knew when he obtained the loans that the proceeds would not be used for the purposes stated in the applications. Kotteakos and 18 others were brought to trial and seven were ultimately convicted, including Kotteakos. At trial, there was evidence that each of the defendants had transacted with Brown, but there was no evidence that any of the defendants had transacted with each other. Kotteakos and the others appealed and their convictions were affirmed by the court of appeals. The U.S. Supreme Court granted certiorari to review.