Decoding expert's testimony and substantial prejudice lead to new trial

US v. Garcia:  Danilo Garcia received five convictions for his alleged involvement in a narcotics trafficking ring that operated between New York City, Philadelphia and Baltimore.  One of three co-defendants out of a group of fourteen people indicted by a grand jury in Maryland, Garcia proceeded to a trial wherein the government presented the testimony of investigating agent/attorney as both a fact witness, based on her observations having listened to thousands of taped phone conversations, and as an expert “decoding” witness, who could testify as to coded meanings the co-conspirators alleged used in the course of the alleged drug trafficking.

On appeal, Garcia challenged the admission of the decoding expert agent’s testimony as well as the denial of his motion for judgment of acquittal for lack of sufficient evidence as to one of the substantive counts of conviction.  The Fourth Circuit reversed the convictions, holding that the admission of the decoding expert’s testimony resulted in substantial prejudice to the defendant because neither the district court’s cautionary instructions, nor the sporadic sustaining of defense counsel’s “early and often, always respectfully” objections, adequately mitigated the risks the testimony presented.

The Fourth Circuit stated that the while the district court manifested a “deep familiarity with this Circuit’s settled guideposts with regard to this type of testimony,” there were problems the district court identified early with respect to this agent’s testimony: the blurring of the distinctions between lay fact testimony (her personal knowledge) on one hand and her expert opinion testimony gained through training and experience on the other; and ensuring that the agent testified on the basis of her experience and expertise in coded language, and not what cooperators or witnesses told her.

The Fourth Circuit found no problem with the agent’s qualifications as an expert, which adhered to Circuit precedent; it did, however, find fault with the nature of her testimony, as well as how extensive and highly influential it was in the jury’s evaluation of the government’s case.  The jury instructions given did not mitigate the prejudice, as a jury might reasonably have assumed that all of the agent’s testimony was based on her decoding expertise, as evidenced by the multiple occasions the agent testified about information she gathered in the investigation - none of which had anything to do with her decoding expertise.  The Fourth Circuit found the agent’s testimony impermissibly exceeded the bounds of Federal Rule of Evidence 702, which contemplates expert evidence “will be ‘helpful to the jury,’ not merely helpful to the prosecutor as transmutations of simple fact testimony.”  The agent’s testimony lacked independent judgment, and the government failed to elicit proper foundations to demonstrate the agent’s claimed reliably-applied methodology.