Along with other vendors, Joseph and Salvatore Falcone (defendants) sold sugar and yeast to purchasers, some of whom had conspired to conduct an illegal distilling operation. The United States government (plaintiff) successfully prosecuted the vendors as co-conspirators. The trial evidence showed that some of the vendors occasionally were present when the distillers discussed their operation, that some vendors raised prices and increased their sales of sugar and yeast once the operation commenced, and that some vendors took steps consistent with disguising their ties to the distillers. Despite the suggestive nature of this evidence, it was insufficient to prove that the vendors knew about or actively participated in the conspiracy. The evidence merely established that the vendors sold sugar and yeast despite knowing that some of the purchasers intended to use those supplies to make whiskey. On appeal, the appellate court ruled that this was not enough to prove that the vendors were co-conspirators. The government appealed to the United States Supreme Court.