Rule 16(a)(1)(G) Rebuttal-Expert Disclosure Is Triggered Only by the Defense’s Timely Disclosed Expert Opinions (Not Undisclosed New Trial Opinions)

1. Introduction

United States v. Crow addresses a procedural question with practical trial consequences: when does the government’s duty to provide pretrial notice of expert rebuttal testimony arise under Federal Rule of Criminal Procedure 16(a)(1)(G) as amended in 2022? The case arose from federal charges that Mitchel Crow sexually abused a minor at a military base under 18 U.S.C. § 2243(a). The sexual conduct itself was not contested—Mr. Crow admitted having sex with the minor—while his state of mind was: he claimed he was asleep (sexsomnia), while the government argued he was awake.

The dispute turned into a “battle of experts.” The defense presented Dr. Clete Kushida, who disclosed pretrial opinions that the reported conduct was consistent with sexsomnia. The government presented Dr. Michel A. Cramer Bornemann, who—based on the complexity of the described steps—opined pretrial that the bedroom encounters were unlikely to be sexsomnia. At trial, however, Dr. Kushida offered new testimony about malingering (false symptom reporting), prompting the government to elicit rebuttal opinions from Dr. Bornemann on that new topic. The defense argued the rebuttal should have been disclosed earlier and that the trial court gave insufficient time to prepare for cross-examination.

2. Summary of the Opinion

The Tenth Circuit affirmed. Assuming (without deciding) that the 2022 amended version of Rule 16 applied, the court held that the government’s rebuttal-disclosure duty under Fed. R. Crim. P. 16(a)(1)(G)(i) (2022) is triggered only for rebuttal testimony “to counter testimony that the defendant has timely disclosed” under the defense expert-disclosure rule. Because the defense had not timely disclosed Dr. Kushida’s malingering opinions before trial, Rule 16 did not require the government to disclose before trial how Dr. Bornemann would rebut those undisclosed new opinions.

The court also declined to entertain a late-raised fairness argument (separate from Rule 16), concluding it was waived because it appeared only in the reply brief.

3. Analysis

A. Precedents Cited

• United States v. Freeman, 70 F.4th 1265, 1286 (10th Cir. 2023).
  The panel cited Freeman for the standard of review: interpretation of the Federal Rules of Criminal Procedure is a legal issue reviewed de novo. This framing mattered because the appeal turned on the meaning and trigger conditions of Rule 16(a)(1)(G), not on discretionary trial-management choices (at least as the appellant presented the issue).
• United States v. Frazier, 387 F.3d 1244, 1269 (11th Cir. 2004).
  The court used Frazier to highlight the pre-amendment baseline: the older Rule 16 required disclosure for expert testimony the government intended to use in its case-in-chief, and (as Frazier put it) rebuttal testimony could historically be presented without prior notice under that version. This contrast set the stage for the 2022 amendment and clarified what the amendment changed—and, critically, what it did not.
• Greenlaw v. United States, 554 U.S. 237, 243 (2008).
  Greenlaw supplied the “principle of party presentation”: appellate courts generally rely on the parties to frame the issues. Here, neither party briefed whether the 2022 amendments applied to this pending case “insofar as just and practicable.” Invoking Greenlaw, the court avoided deciding the applicability question and instead assumed the amended rule applied “for the sake of argument,” allowing resolution on narrower grounds.
• United States v. Leffler, 942 F.3d 1192, 1197-98 (10th Cir. 2019).
  The court relied on Leffler for a familiar appellate constraint: arguments first raised in a reply brief are waived. That doctrine foreclosed Mr. Crow’s attempt to repackage his claim as “unfairness” independent of Rule 16.

B. Legal Reasoning

The panel’s reasoning proceeds in three steps:

1. Assume the amended rule applies, then interpret its trigger.
   Without resolving the “just and practicable” retroactivity question for pending cases, the court assumed the 2022 amendment governed. Even under that assumption, the decisive language was that rebuttal disclosure is required only for rebuttal “to counter testimony that the defendant has timely disclosed under (b)(1)(C).”
2. Define what the defense timely disclosed vs. what emerged at trial.
   The defense’s pretrial disclosure described Dr. Kushida’s opinion as one of consistency: Mr. Crow’s conduct “could have been the result of” sexsomnia / NREM parasomnia. The report did not opine on malingering, Mr. Crow’s truthfulness, or whether specialized forensic psychiatry or testing was needed to assess malingering. At trial, however, Dr. Kushida added new malingering-related opinions—specifically, that he did not believe Mr. Crow was malingering when reporting his memory and symptoms. That was the first time the defense introduced an expert opinion on truthfulness/malingering in this case.
3. Apply the trigger to the facts: no timely defense disclosure, no government rebuttal-disclosure duty.
   Because the malingering opinions were not part of the defense’s timely disclosure, Dr. Bornemann’s rebuttal opinions addressing malingering were not rebutting “testimony that the defendant has timely disclosed.” The court stressed the practical logic: the government cannot be expected to provide pretrial notice of how it will rebut opinions the defense itself did not reveal before trial.

The court also rejected two defense attempts to bring the rebuttal within Rule 16’s scope:

• “The rebuttal really addressed the report.” The court disagreed: the report was about sexsomnia consistency and did not include malingering opinions.
• “The government opened the door on cross.” The court distinguished (a) acknowledging “secondary gain” as an objective incentive in the circumstances from (b) an expert’s new, affirmative opinion that the defendant was truthful and not malingering. The latter was new expert opinion testimony, not previously disclosed.

Notably, the opinion confines itself to the argument presented—Rule 16(a)(1)(G)(i)—and explicitly avoids addressing the separate supplementation duty under Rule 16(c), because the appellant disclaimed reliance on it.

C. Impact

1) A disciplined trigger for the 2022 rebuttal-disclosure amendment.
The decision gives a limiting construction to the expanded rebuttal-disclosure regime: the government’s new obligation does not become an all-purpose requirement to anticipate every possible trial turn. It is keyed to what the defense timely disclosed, preserving the amendment’s symmetry and preventing surprise expansions by undisclosed defense testimony from generating instant pretrial disclosure duties.

2) Incentives for complete defense expert disclosures—and risks of “trial-only” opinions.
If defense experts introduce new opinions at trial (especially on collateral but powerful topics like malingering/credibility), Crow signals that the defense may lose the benefit of pretrial notice of the government’s rebuttal on those new opinions. Practically, this increases the premium on disclosing the full expected scope of expert testimony early, or at least seeking leave to supplement disclosures in time for reciprocal rebuttal notice.

3) Trial-court management remains important, but appellate review may be constrained by issue framing.
The court refused to consider a generalized unfairness theory raised only in the reply brief. Litigants seeking more preparation time for newly developing rebuttal should preserve that argument distinctly (not solely as a Rule 16 violation), and develop a record tied to continuance standards and prejudice.

4) Likely downstream questions.
The opinion leaves open how Rule 16(c)’s supplementation duty might apply when expert opinions evolve mid-trial, and how courts should address situations where cross-examination legitimately elicits new expert opinions. Future cases may test whether “timely disclosed” includes disclosures made shortly before trial, late supplements, or court-ordered rolling disclosures—and what remedies are appropriate when either side’s experts pivot.

4. Complex Concepts Simplified

• Case-in-chief vs. rebuttal: The case-in-chief is the government’s main presentation of evidence. Rebuttal is evidence offered after the defense case to respond to what the defense presented.
• Rule 16(a)(1)(G) expert disclosures: A rule requiring written summaries of expert testimony (opinions, bases, qualifications, prior testimony lists in the amended framework). In 2022, it was amended to include certain rebuttal disclosures too.
• “Timely disclosed”: Disclosed within the deadline the rule, court order, or scheduling order requires. Under Crow, the government’s rebuttal-disclosure duty attaches only to rebuttal addressing what the defense timely disclosed.
• Malingering: Deliberately feigning or exaggerating symptoms for an external benefit (e.g., avoiding responsibility). In forensic settings, it can be a significant issue because it bears on the reliability of claimed symptoms and memory.
• Sexsomnia / NREM parasomnia: Sleep-related disorders involving abnormal behaviors during sleep; sexsomnia refers to sexual behavior occurring during sleep.
• De novo review: The appellate court reviews the legal question fresh, without deferring to the district court’s interpretation.
• Forfeiture vs. waiver (as reflected in the opinion’s discussion): Forfeiture is failure to raise an issue; waiver can include failing to timely present an argument (e.g., raising it only in a reply brief), which often bars appellate consideration.
• Principle of party presentation: Courts generally decide cases on the issues the parties actually argue, not on alternative theories the court could raise itself.

5. Conclusion

United States v. Crow crystallizes an important boundary on the 2022 expansion of Rule 16 expert rebuttal disclosures: the government’s duty to provide pretrial notice of rebuttal expert testimony is triggered only when the rebuttal counters expert opinions the defense timely disclosed. When the defense expert adds undisclosed new opinions at trial—here, malingering-related opinions—the government has no Rule 16(a)(1)(G)(i) obligation to have disclosed its rebuttal to those opinions before trial. The ruling encourages complete and timely expert disclosures, reinforces the textual trigger built into the amended rule, and cautions litigants to preserve non-Rule-16 trial fairness arguments in a timely, standalone manner.