United States v. Vera

If a law enforcement officer testifies at trial as both a lay witness and an expert witness, the jury must be instructed as to the differences and significance of the separate roles so as not to give undue weight to lay witness testimony in violation of the Confrontation Clause.

In 2007, The Santa Ana Gang Task Force received information from an informant of heavy drug trafficking activity in a highly populated apartment complex. Based on the tip, officers were led to the Defendants, who were high-level gang members. The officers began wiretapping the Defendant’s phone calls. At trial, two officers who investigated this case testified as expert witnesses. One officer testified as an expert on gang culture, and the other as an expert on drug jargon. The Defendant’s contend that the testimony of both officers was improper because it impermissibly mixed expert and lay opinions and violated their rights under the Conformation Clause. The Ninth Circuit explained that to determine whether an expert has complied with the requirements of the Confrontation Clause is to inquire as to whether the officer formed his opinion by “applying extensive experience and reliable methodology.” The panel found that the expert testimony on gang culture was not improper because the officer applied his own personal experiences to his observations to form an expert opinion about this particular gang’s tactics. The panel did take issue with the drug jargon expert’s testimony. The panel explained that if one officer testifies as both a lay witness and an expert witness, the jury must be educated of the differences and significance of the separate roles. Here, there was no instruction for the jury on how to evaluate the drug jargon expert’s testimony. The panel concluded that such an error undermined the validity of the jury verdict as it resulted in an inaccurate representation of the quantity of drugs to the jury, which affected the minimum sentences faced by the defendants. The panel vacated the findings related to the quantity of drugs and affirmed the remainder of the verdict. AFFIRMED IN PART, VACATED IN PART AND REMANDED.