by Anthony W. Accurso

The U.S. Court of Appeals for the Ninth Circuit ruled that the U.S. District Court for the District of Arizona failed in its gatekeeping function when it allowed an ICE agent to testify on the probability of a Mexican drug cartel using a coerced truck driver despite there being no reliable methodology underpinning the agent’s testimony.

Enrique Valencia-Lopez was indicted on federal drug charges for driving a truck containing bell peppers and 6,230 kilos of marijuana across the U.S. border into Arizona. Valencia-Lopez claimed that he had been detained by cartel thugs in Mexico while his truck was taken for an indeterminate period of time. Once it was returned, he said he was instructed to complete his trip as if nothing happened or his family would be in danger.

Valencia-Lopez presented this defense at trial. He did not challenge that he knowingly committed the offense but instead argued that he was coerced into doing so.

The only witness the Government presented to counter his coercion defense was U.S. Immigration and Customs Enforcement Supervisory Special Agent Matthew Hall, who, according to pre-trial filings, would testify about the risks posed to cartel business operations regarding the use of coerced carriers.

Defense counsel objected to Hall being used as an expert, requesting Daubert hearing because “there [was] no methodology whatsoever to substantiate Agent Hall’s proposed testimony,” and Hall lacked relevant expertise. This request was denied, and Hall went on to testify that “the likelihood regarding whether [cartels] would entrust large quantities of illegal drugs to the driver of a commercial vehicle who’s been forced or threatened to comply” was “almost nil, almost none.”

Defense counsel objected again, but the court noted Hall’s experience as an agent (though he lacked any direct experience with cartels in Mexico) and stated the objection went “more to the weight of the evidence as opposed to its admissibility.”

Valencia-Lopez was convicted and sentenced to 10 years’ imprisonment and timely appealed.

The Court noted that Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), and Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999), describe a district court’s gatekeeping role regarding expert testimony under Federal Rule of Evidence 702.

Under Rule 702, the court must “ensur[e] that the testimony is both ‘relevant’ and ‘reliable.’” United States v. Ruvalcaba-Garcia, 923 F.3d 1183 (9th Cir. 2019) (citing Daubert). This “applies to all expert testimony,” not just scientific experts. United States v. Hermanek, 289 F.3d 1076 (9th Cir. 2002) (citing Kumho Tire). While district courts have broad latitude to determine reliability, it must not “abdicate completely” this responsibility. Elsayed Mukhtar v. Cal. State Univ., Hayward, 299 F.3d 1053 (9th Cir. 2002). Citing Ruvalcaba-Garcia, the Court explained that “a district court abdicates its gatekeeping role, and necessarily abuses its discretion, when it makes no reliability findings.”

The Court found that Hall had sufficient expertise in the field, but “the record contains no evidence as to why that experience, by itself, equals reliability for his testimony” regarding the statistical likelihood to which he testified.

The Ninth Circuit had previously explained that the district court’s role includes a “preliminary assessment of whether the reasoning or methodology underlying the testimony is ... valid and whether that reasoning or methodology properly can be applied to the facts in issue.” Hermanek. It is the Government’s burden to “establish the reliability of the principles and methods employed” by its witness during testimony, the Court stated.

The Court concluded that, not only did the Government fail in its duty under Fed. R. Crim. P. 16(a)(1)(G) to properly disclose what matters on which Hall would testify, but it failed to establish any methodology that could underlie Hall’s determination of the probability he asserted. Also, since Agent Hall’s testimony was the only evidence opposing Valencia-Lopez’s claim of coercion, and it was reiterated during the Government’s closing remarks, the Court determined this likely contributed to his conviction, thus violating his right to a fair trial.

Thus, the Court held the district court abdicated its duty to screen Agent Hall’s expert testimony for reliability.

Accordingly, the Court vacated Valencia-Lopez’s conviction and remanded for a new trial. See: United States v. Valencia-Lopez, 971 F.3d 891 (9th Cir. 2020). 

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