D and Hernandez-Coronel (D) were convicted for importing and distributing heroin. A paid informer who had worked on prior occasions with DEA, initiated a series of telephone conversations with D, who was staying in Mexico. The parties eventually met and discussed delivery and transportation of heroin in further detail. A sale was eventually arranged. It was agreed that delivery of the drugs would be in United States. Ds were arrested. At trial, Ds contend the court erred in permitting testimony that related their conversations with the informers when in fact the meetings were recorded on tapes. Ds contend under the best evidence rule that the tapes were the best evidence of the conversations. Ds appealed.