Admitting Expert Testimony: Federal Judge’s Gatekeeper Role

Courts have characterized the judge’s job in evaluating the admissibility of evidence as that of a gatekeeper.  The judge’s duty is to consider the relevance of the evidence for the purpose it is sought to be admitted, its reliability and its unfair prejudicial effect, as well as other considerations.

The following U.S. Court of Appeals decision from the Ninth Circuit in Pasadena exemplifies that role and it helpful to understand if one is trying to admit or exclude certain evidence in one’s particular case.

Enrique Holguin, Emanuel Higuera and Donald Goulet were convicted of conspiracy in violation of the Racketeer Influenced and Corrupt Organizations (“RICO”) (18 U.S.C. § 1962(d)) in federal court arising from drug trafficking (methamphetamine), money laundering activity and certain violent crimes allegedly committed on behalf of Canta Ranas, a multi-generational Whittier-based street gang with ties to the Mexican Mafia.  Holguin, Higuera and Goulet were charged in a sweeping indictment along with dozens of other individuals associated with Canta Ranas.

Before trial, they each filed motions in limine to exclude the government’s proposed expert witness testimony of Whittier Police Officer Robert Rodriguez, former Mexican Mafia member Rene Enriquez, and DEA Special Agent Steven Paris and requested a Daubert hearing.  Daubert v. Merrell Dow Pharms., Inc. (1993) 509 U.S. 579, 584-587. 

The trial court denied the request for a Daubert hearing, tentatively denying the motions in limine and allowed the expert testimony without explanation.

The experts then provided background information to the jury about Canta Ranas and explained how the gang operates.  They explained how the gang generates revenue through criminal activity, explained gang language and monikers and how senior gang members distributed narcotics to foot soldiers to sell.

The Ninth Circuit agreed with Holguin, Higuera and Goulet that the district court judge erred in failing to make explicit findings that the government’s expert testimony was reliable, as required by United States v. Ruvalcaba-Garcia (9th Cir. 2019) 923 F.3d 1183, 1190.  An “implicit” finding does not suffice.  Id; see also United States v. Irons (9th Cir. 2022) 31 F.4th 702, 716.  This requirement ensures that district courts engage in the reliability inquiry and create a record of that inquiry to facilitate appellate review.

It merits mention here that Holguin, Higuera and Goulet did not argue that the district court erred in failing to make findings about the experts’ qualifications.  Any such errors would be regarded as harmless.  See United States v. Figueroa-Lopez (9th Cir. 1997) 125 F. 3d 1241 at 1247.

It also merits mention that the Ninth Circuit did not find error in the district court not holding a specific hearing to rule on the reliability of the experts, but the district court nonetheless abused its discretion by not otherwise making explicit findings regarding the reliability of the expert testimony.  The Ninth Circuit, however, commented that “it would have been prudent to hold such a hearing.”  This is the essence of the “gatekeeping” role and duty.

Nonetheless, the Ninth Circuit held that the district court’s abuse of discretion in this regard “does not warrant a reversal of appellants’ convictions [b]ecause the trial record shows that the government’s expert witnesses had sufficient relevant experience and gave adequate explanations for their interpretations of letters and phone calls and thus the district court’s error was harmless.” 

Indeed, Federal Rule of Evidence, Rule 702, gives district courts “broad latitude” to structure proceedings concerning expert testimony.  Kumho Tire Co. v. Carmichael (1999) 526 U.S. 137, 142.  The Rule 702 inquiry is “flexible” and “must be tied to the facts of a particular case.”  United States v. Alatorre (9th Cir. 2000) 222 F. 3d 1098, 1102.

The Ninth Circuit explained that the error was harmless for because, for example, Officer Rodriguez’s testimony was supported by ten years of investigating gang crimes with the Whittier Police Department.  Rene Enriquez’s testimony, similarly, was supported by seventeen years of personal participation in the Mexican Mafia.  Lastly, Agent Paris’s testimony was supported by twenty-seven years of experience conducting thousands of drug investigations, many involving Hispanic gangs.

For more information about a judge’s “gatekeeping” role in screening evidence before admission, please click on the following articles: