In United States v. Rivera, 859 F.2d 1204 (4th Cir. 1988), cert. denied, 490 U.S. 1020, 104 L. Ed. 2d 180, 109 S. Ct. 1743 (1989), the Fourth Circuit held that the trial court had not erred in declaring three illegal aliens who had been deported by the United States to be unavailable within the meaning of Rule 804(a) of the Federal Rules of Evidence. The government had used a deposition of one of the aliens and parts of two other depositions at Rivera's trial. Rivera argued that the witnesses were not unavailable because the government, by its own actions, had deported them. The Court of Appeals noted that, actually, the witnesses had left the United States voluntarily, and the court had acted appropriately in permitting them to be deposed rather than keeping them in custody. Id. at 1207. The Court of Appeals further noted that the United States Attorney had a duty to consider the rights of the witnesses as well as those of appellant. Id.