United States v. Dias: Prior Felon-in-Possession Convictions Are Generally Irrelevant Rule 404(b) “Knowledge” Evidence in Actual-Possession § 922(g)(1) Trials (Absent Unusual Facts)

1. Introduction

In United States v. Dias, the Tenth Circuit affirmed a felon-in-possession-of-ammunition conviction and a substantial upward-variance sentence, but it did so while making an important evidentiary clarification: where the government’s theory is that the defendant actually possessed (here, fired) a gun/ammunition, “knowledge” is ordinarily not a fact “of consequence,” and a prior felon-in-possession conviction offered under Federal Rule of Evidence 404(b) to prove “knowledge” is therefore generally irrelevant and inadmissible—absent unusual circumstances (e.g., a claim the object was not known to be a gun).

The case arose from a 2024 incident in which the victim, B.A., returned home to find Michael Joseph Dias inside his apartment. After a struggle and chase outside, B.A. reported that Dias pulled a gun and fired one or two shots. Police recovered a fresh nine-millimeter shell casing but never found the firearm. A jury convicted Dias under 18 U.S.C. § 922(g)(1) for possessing ammunition as a felon. The district court varied upward from a 63–78 month Guidelines range to 120 months.

On appeal, Dias challenged: (1) admission of his prior felon-in-possession conviction under Rule 404(b), (2) sufficiency of the evidence, (3) substantive reasonableness of the upward variance, and (4) facial constitutionality of § 922(g)(1) under the Second Amendment.

2. Summary of the Opinion

• Rule 404(b): The Tenth Circuit agreed (and noted the Government conceded at argument) that the district court erred by admitting Dias’s 2019 felon-in-possession conviction to show “knowledge,” because knowledge was not genuinely at issue given the government’s actual-possession theory. The evidence was not relevant under Rule 401 and risked an impermissible propensity inference barred by Rule 404(b)(1).
• Harmless error: The error was harmless in context: the challenged evidence was presented briefly, not emphasized, and the Government’s remaining proof (eyewitness testimony, contemporaneous 911 and bodycam corroboration, and a recently fired casing) was strong; plus the jury received a limiting instruction.
• Sufficiency: Evidence was sufficient; credibility disputes about B.A. were for the jury.
• Sentence: The 120-month sentence was substantively reasonable; the district court could rely on the seriousness of conduct and recidivism even if the Guidelines already accounted for related factors, and it was not required to consult national sentencing statistics.
• Second Amendment: Facial challenge foreclosed by circuit precedent (Vincent v. Bondi).

3. Analysis

3.1. Precedents Cited

A. Elements and mens rea under § 922(g)(1): Rehaif v. United States

The court framed the Government’s burden using Rehaif v. United States, requiring proof that Dias knowingly possessed ammunition and knew of his felony status. The parties stipulated to everything except knowing possession (element one). This set the stage: if “knowledge” collapses into the fact of actual possession (holding/firing), “knowledge” may be technically an element but not a practically disputed one—driving the Rule 401/404(b) relevance analysis.

B. The Rule 404(b) framework: United States v. Irving

Applying the four-part test from United States v. Irving—proper purpose, relevance, Rule 403 balance, and limiting instruction—the opinion concentrates on relevance and the danger that “knowledge” is a pretext for propensity.

C. Tenth Circuit constructive-possession precedents distinguished: United States v. McGlothin and United States v. Moran

The district court relied on United States v. McGlothin and United States v. Moran to admit the prior conviction. The panel explains why those cases do not translate to an actual-possession prosecution:

• McGlothin: Prior handgun possession was relevant where the defense contested dominion/control over a gun found in an apartment bedroom (a classic constructive-possession dispute). Prior acts could make it more probable that the defendant was the knowing possessor.
• Moran: Prior felon-in-possession convictions were relevant where the defendant claimed he did not know a rifle was in the vehicle—placing “knowledge of presence” squarely in dispute.

In short, McGlothin and Moran are positioned as constructive-possession/knowledge-of-presence cases—contexts in which “knowledge” is genuinely “of consequence.”

D. Sister-circuit “actual possession” rule embraced: United States v. Caldwell, United States v. Linares, United States v. Jones

The opinion adopts the logic of United States v. Caldwell (Third Circuit), which holds that when the government alleges actual possession, knowledge is “almost never a material issue,” absent unusual circumstances (e.g., not realizing the object was a gun). The Tenth Circuit also cites:

• United States v. Linares (D.C. Cir.): prior felon-in-possession conviction inadmissible where no reasonable jury could find possession was unknowing or mistaken.
• United States v. Jones (5th Cir.): prior felon-in-possession conviction not relevant to proving actual possession.

Although the panel notes the Tenth Circuit had not previously “had occasion to adopt this rule,” it explicitly sees “no reason to depart” from these circuits—functionally establishing the same relevance principle in Tenth Circuit law.

E. Harmless-error doctrine and calibration: United States v. Poterbin, United States v. Jean-Pierre, United States v. Kupfer, United States v. Blechman, United States v. Summers, United States v. Merritt, and the limiting case United States v. Commanche

Having found error, the court pivots to harmlessness, using:

• United States v. Poterbin: erroneous 404(b) admission is not reversible if harmless; also notes the role of “significant other evidence.”
• United States v. Jean-Pierre: defines harmless error (“substantial influence” / “grave doubt”) and places the burden on the Government.
• United States v. Kupfer: instructs reviewing the entire record de novo, including context, timing, use, and comparison to properly admitted evidence.
• United States v. Blechman: emphasizes probative value of the bad-acts evidence and overall strength of the government’s case as “critical factors.”
• United States v. Summers: restates the harmlessness formulation applied at the end of the analysis.
• United States v. Merritt: highlights that strong evidence plus a proper limiting instruction often renders erroneous admission harmless.

The court distinguishes United States v. Commanche, where the erroneously admitted prior violent conduct bore directly on the single disputed issue (self-defense and the reasonableness of force) and was described in a way that made the propensity inference unavoidable. In Dias, the prior conviction was mentioned briefly, details were not explored, it was not argued in opening/closing, and the limiting instruction mitigated prejudice.

The panel also cites non-Tenth Circuit harmlessness examples—United States v. McCallum and United States v. Tarver—to reinforce that minimal emphasis on prior convictions tends to support harmlessness.

F. Sufficiency review guardrails: United States v. Leffler, United States v. Goldesberry, United States v. Bass, United States v. Pearson

To reject the sufficiency challenge, the court relies on:

• United States v. Leffler: de novo sufficiency standard in the light most favorable to the prosecution.
• United States v. Goldesberry: “highly deferential” sufficiency review; also the “equal circumstantial support” rule—held inapplicable because the Government presented direct evidence (B.A.’s account) here.
• United States v. Bass: credibility determinations are for the jury; testimony is disregarded only if “unbelievable on its face.”
• United States v. Pearson: minor inconsistencies do not meet the “unbelievable” threshold.

G. Substantive reasonableness and variances: United States v. Jackson, United States v. Cookson, United States v. Maldonado-Passage, United States v. Miller, United States v. Gross, United States v. Smart, United States v. Lucero, United States v. Mumma, United States v. Mateo, United States v. Proffit, Gall v. United States, United States v. Guevara-Lopez, United States v. Barnes

The panel’s sentencing analysis is largely an application of established principles:

• United States v. Cookson and United States v. Jackson: distinguish procedural and substantive reasonableness; focus here is substantive.
• United States v. Maldonado-Passage, United States v. Miller, United States v. Gross: articulate deference and the “range of rationally available choices” standard; reversal only if “arbitrary, capricious, whimsical, or manifestly unreasonable.”
• United States v. Smart and United States v. Lucero: district courts may “contextually evaluate” § 3553(a) factors even when Guidelines account for them.
• United States v. Mumma, United States v. Mateo, United States v. Proffit: similarity-driven recidivism and “penchant for criminality” can justify upward variances as deterrence/incapacitation rationales.
• Gall v. United States: disparity consideration is satisfied by correct Guidelines calculation and an adequate explanation for variance.
• United States v. Guevara-Lopez: courts need not consult Sentencing Commission national statistics; must explain significant variances.
• United States v. Barnes: no algorithm for weighting § 3553(a) factors; not every factor must be explicitly relied upon.

H. Second Amendment: Vincent v. Bondi

Dias’s facial challenge to § 922(g)(1) was raised for preservation only and rejected as foreclosed by Vincent v. Bondi.

3.2. Legal Reasoning

A. The opinion’s key evidentiary holding: relevance, not “proper purpose,” does the work

The district court admitted the prior conviction for the “proper purpose” of proving knowledge, a purpose listed in Rule 404(b)(2), and gave a limiting instruction. Dias nonetheless finds an abuse of discretion because “knowledge” was not a “fact of consequence” in the circumstances presented. The panel’s reasoning proceeds in three linked steps:

• Rule 401 constraint: Evidence is relevant only if it makes a consequential fact more or less probable.
• Actual possession collapses the knowledge issue: Absent “unusual facts,” a rational jury cannot conclude a defendant physically held and fired a gun “unknowingly.” Thus, if the jury believes the possession occurred, the knowledge element follows automatically; if the jury disbelieves possession, the case fails anyway.
• Propensity risk: In that posture, the only meaningful inferential use of a prior felon-in-possession conviction is “once a gun possessor, always a gun possessor”—the forbidden character-to-conduct inference under Rule 404(b)(1).

This is a notable clarification because it limits the government’s ability to repackage propensity as “knowledge” when the case is tried as a straightforward “he had it in his hand” contest.

B. Harmless error: how the court avoids reversal while still announcing the evidentiary rule

Despite finding error, the panel affirms by emphasizing:

• Strength of properly admitted evidence: B.A.’s testimony that Dias produced and fired the gun; consistency with 911 and on-scene accounts; video capturing the confrontation; and recovery of a fresh casing with contextual support (no similar incidents in six months).
• Limited “dose” of prior-conviction evidence: The Government elicited only a brief acknowledgment (no details), did not reference it in opening/closing, and did not attempt to build a “similarity” narrative.
• Limiting instruction: The jury was instructed to consider the prior act only as it bore on “intent and/or knowledge,” and not as proof Dias committed the charged act.

The court’s distinction of Commanche is important: it signals that harmless-error outcomes in 404(b) cases are highly sensitive to (i) whether the case turns on an issue closely tied to character and (ii) whether the government developed the prior act in a way that makes propensity reasoning irresistible.

C. Sufficiency: direct eyewitness testimony plus corroboration defeats “equipoise” framing

Dias attempted to reframe the record as equally supportive of guilt and innocence (suggesting B.A. fired the shots). The panel rejected this, holding that credibility disputes and claimed inconsistencies are for the jury unless testimony is physically impossible. Because the Government introduced direct evidence (B.A.’s account) plus corroboration, Goldesberry’s “equal circumstantial support” concept did not compel reversal.

D. Sentencing: upward variance justified by offense seriousness and similarity-based recidivism

The sentencing holding rests on familiar deference principles: district courts may weigh § 3553(a) factors heavily, even if the Guidelines accounted for some of the same information, and similarity of prior offenses can legitimately inform recidivism and deterrence assessments. The court also reinforces that national sentencing statistics (including JSIN) are not required inputs; a correct Guidelines calculation and an adequate explanation suffice under Gall v. United States and United States v. Guevara-Lopez.

3.3. Impact

A. Trial practice in § 922(g)(1) cases: narrowing “knowledge” as a gateway for prior gun-possession evidence

The most consequential impact is evidentiary. Dias effectively establishes that, in the Tenth Circuit, the government generally cannot introduce a defendant’s prior felon-in-possession conviction under Rule 404(b) to prove “knowledge” when the theory is actual possession and the defense does not raise an “unusual” knowledge issue (e.g., mistaken identity of the object). This invites:

• More successful motions in limine to exclude prior § 922(g) convictions in “officer saw a gun” or “victim saw a gun” cases.
• More careful charging and proof choices: prosecutors may attempt to frame cases (where plausible) as constructive possession/knowledge-of-presence disputes to keep knowledge material, though that must be faithful to the evidence.
• Cleaner appellate records: if prosecutors avoid unnecessary 404(b) admissions, they reduce the risk of reversal where evidence is closer than in Dias.

B. Harmless-error signaling: when the government may still survive an erroneous 404(b) admission

At the same time, Dias underscores that not every erroneous admission of a prior gun conviction will result in reversal. The decision provides a practical roadmap: minimal emphasis, no details, no summation reliance, strong corroborated proof, and a limiting instruction are the factors most likely to yield harmlessness.

C. Sentencing variance doctrine: continued endorsement of similarity-based recidivism

While less novel, the sentencing portion reinforces that “recidivist conduct” and offense seriousness can justify substantial upward variances, and that disparity arguments based on national data will not prevail absent a showing that the district court’s explanation was inadequate or irrational.

4. Complex Concepts Simplified

• Rule 404(b): A rule that generally bars evidence of prior crimes to show someone’s “bad character,” but allows it for specific non-propensity purposes (like knowledge or intent) when genuinely relevant.
• Rule 401 “fact of consequence”: Even if evidence relates to an element in the abstract, it must matter in the real dispute the jury must decide. If the jury’s choice is simply “did he have the gun or not,” a prior conviction rarely helps decide a meaningful “knowledge” question.
• Actual vs. constructive possession: “Actual” means in-hand/physical control; “constructive” means control over the place or ability to control the item even if not holding it. Knowledge disputes are more common in constructive possession cases (e.g., “I didn’t know it was in the car”).
• Propensity inference: Reasoning that because someone did it before, they likely did it again. Rule 404(b)(1) prohibits using prior crimes for that purpose.
• Harmless error: Even if the trial court made a legal mistake, the conviction stands if the appellate court is convinced the mistake did not substantially affect the verdict.
• Upward variance: A sentence above the advisory Guidelines range based on the judge’s assessment of the statutory sentencing factors in 18 U.S.C. § 3553(a).
• Facial constitutional challenge: An argument that a statute is unconstitutional in all its applications; here foreclosed by circuit precedent.

5. Conclusion

United States v. Dias affirms a conviction and an above-Guidelines sentence, but it does so while announcing a significant evidentiary constraint in the Tenth Circuit: when the government proceeds on an actual-possession theory in a § 922(g)(1) case, a prior felon-in-possession conviction is generally not relevant “knowledge” evidence under Rule 404(b) because knowledge is rarely a consequential fact—making the prior conviction functionally propensity evidence.

The decision’s broader significance lies in its alignment with sister circuits on this point and its practical guidance on harmless-error analysis. For litigants, Dias strengthens Rule 404(b) challenges in straightforward actual-possession prosecutions while simultaneously demonstrating how appellate courts may still affirm where the improper evidence was brief, not emphasized, and the remaining proof is strong.