Gang expert’s testimony did not violate defendants’ confrontation clause rights because his opinion was developed by applying his experience and methodology and was not merely a conduit for testimonial hearsay. Defendants were convicted of federal drug offenses. On appeal they challenged admission of expert testimony regarding gangs and drug jargon. Held: Reversed in part. The Supreme Court held in Crawford v. Washington (2004) 541 U.S. 36, that admission of testimonial statements of a witness who does not appear at trial violates a defendant’s confrontation clause rights. There is generally no problem under Crawford when an expert applies his expertise and a reliable methodology to derive an opinion based on such inadmissible testimonial hearsay, if it is of a type reasonably relied upon by experts. However, the witness may not act as a conduit for testimonial hearsay in the guise of expert opinion. Here, Detective Franks testified about gang structure generally and defendants’ gang specifically. He applied his experience to his observations to form an opinion about the gang and their tactics. His testimony was not “merely repackaged testimonial hearsay but was an original product that could have been tested through cross-examination.”

Where an expert in drug jargon intermingled lay witness and expert opinion testimony, the court’s failure to explain the difference to the jury requires reversal of drug quantity findings. FBI Agent Lavis interpreted calls recorded as part of the drug investigation, explaining drug jargon; this is an appropriate subject for expert testimony. The expert may also testify as a lay witness if he was involved in the investigation. But such hybrid testimony causes concerns the expert’s status could lend him unmerited credibility as a percipient witness, inhibit cross-examination, and confuse the jury. These risks are reduced where the jury is instructed regarding the witness’ dual roles. Here, the trial court stated it would instruct the jury how to distinguish between expert and lay testimony, and that the “facts” upon which Lavis relied in forming his expert opinion could not be considered for their truth. However, it did not do so. This, along with the failure to establish an adequate foundation for the testimony, was prejudicial error because it increased the risk that the jury gave Lavis’ testimony undue deference. Because the error affected the drug quantity findings, which increased the defendants’ sentences, but not the elements of the offense, only the quantity findings were reversed.