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Case 1:20-cr-00330-PAE Document 393 Filed 10/29/21 Page5of10 At the same time, three of the government’s other witnesses Re) 20° law enforcement officers. Because the government frequently attempts to elicit expert opinion testimony from law enforcement officers without disclosing them as experts under Federal Rule of Criminal Procedure 16 or qualifying them as experts under Federal Rule of Evidence 702, and because law enforcement witnesses often offer opinion testimony about the defendant’s mental state and vouch for the truthfulness or bolster the credibility of alleged victims in contravention of Federal Rule of Evidence 704, this Court should grant this motion in /imine. ARGUMENT Federal Rule of Evidence 702 governs expert opinion testimony at trial. It says: A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if: (a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) the testimony is the product of reliable principles and methods; and (d) the expert has reliably applied the principles and methods to the facts of the case. Fed. R. Evid. 702. If a law enforcement officer gives testimony that “depend|[s], in whole or in part, on his specialized training and experience,” the testimony is expert opinion testimony subject to Rule 702 and not lay opinion testimony subject to Rule 701. United States v. Garcia, 413 F.3d 201, 216 (2d Cir. 2005) (“We hold that the foundation requirements of Rule 701 do not permit a law enforcement agent to testify to an opinion . . . if the agent’s reasoning process depended, in whole or in part, on his specialized training and experience.”). DOJ-OGR-00005751