The United States Supreme Court recently addressed the question of whether the Confrontation Clause of the Sixth Amendment is violated when a substitute analyst provides expert witness testimony about the results of forensic testing performed by a non-testifying analyst.
The Court held that when an expert, in this instance a substitute analyst, presents the out-of-court statements of another analyst as the basis for their own expert opinion, the statements are being offered for their truth.
This implicates the Confrontation Clause because the defendant is not able to cross-examine the original analyst about the testing procedures and results.