Using absent witnesses' statements

1. Whether the Sixth Amendment’s Confrontation Clause permits the Government to prove a defendant’s identity as the source of supply in a narcotics conspiracy through the out-of-court statements of a non-testifying intermediary, Andrea Mitchell, where the Government did not produce Mitchell for cross-examination and instead relied on recorded statements, law-enforcement narration, and agent interpretations of her words to establish the defendant’s role. 2. Whether the evidence was constitutionally sufficient to support conspiracy and possession-with-intent-to-distribute convictions when no witness observed petitioner transfer narcotics to Mitchell, no video or photograph captured a hand-to-hand exchange, and the Government’s case depended largely on Mitchell’s uncrossed out-of-court statements, call timing, and surveillance inferences. 3. Whether the district court’s admission and use of Mitchell’s uncrossed statements, viewed cumulatively with the inferential proof offered at trial, denied petitioner the fair trial guaranteed by the Sixth Amendment and the Due Process Clause.