The United States government (plaintiff) prosecuted Ernesto Llanos Domenich (Llanos), Ruben Ortiz De Jesus (Ortiz), and Ortiz's brother-in-law Felix Nunez Molina (Nunez) (defendants) for illegal cocaine trafficking. Viewing the conflicting evidence in the light most favorable to the government, the trial jury was warranted in finding that Llanos arranged to sell cocaine to an undercover federal agent, and asked Nunez to accompany him to the sale site. Nunez agreed to do so. Llanos and Nunez remained in their car throughout the ensuing exchange with the agent. Llanos handed the agent a packaged kilogram of cocaine, which the agent said was more than he wished to buy. Llanos replied that he would have to cut and repackage the cocaine, and then return to the sale site. Nunez concurred. Before returning, Llanos asked Ortiz to join him and Nunez, and Ortiz agreed. Ortiz carried a beeper. As before, Llanos and his confederates remained in their car throughout the ensuing exchange. Nunez showed the repackaged cocaine to the agent. The agent left, ostensibly to get money to complete the purchase, at which point other federal agents arrived and arrested Llanos, Ortiz, and Nunez. Llanos pleaded guilty of being the principal in the cocaine sale. The jury found Ortiz and Nunez guilty of aiding and abetting Llanos. Ortiz and Nunez appealed their convictions to the United States Court of Appeals for the First Circuit.