Rule 403 and Rule 701 Limits on “Murder-Trial” Proof in a § 922(g) Case—Errors Deemed Harmless Amid Strong Circumstantial Evidence

I. Introduction

United States v. Lamar McCullough (3d Cir. Aug. 4, 2026) arises from a March 5, 2021 shooting in Newark, New Jersey. Although the government repeatedly framed the trial as about a close-range shooting, the sole federal charge tried to the jury was felon-in-possession of ammunition under 18 U.S.C. § 922(g)(1).

On appeal, Lamar McCullough challenged (1) evidentiary rulings that allowed the government to introduce graphic blood photographs and to elicit a detective’s lay opinion identifying McCullough as the shooter in video footage, and (2) the sentencing court’s use of the Guidelines’ cross-reference to attempted murder.

The Third Circuit (nonprecedentially) held that the District Court committed two evidentiary errors under Federal Rules of Evidence 403 and 701, but affirmed because the errors were harmless in light of the overall record. It also affirmed the Guidelines calculation applying the attempted-murder cross-reference.

II. Summary of the Opinion

  • Rule 403 error: The District Court should have excluded three crime-scene photos showing blood but not ammunition. Their probative value (at most, explaining investigative sequence) was minimal and their unfair prejudice substantial.
  • Rule 701 error: The court improperly admitted a detective’s lay opinion identifying McCullough as the shooter in video. The detective lacked the required first-hand perceptual basis and the opinion was not “helpful” in the Rule 701 sense.
  • Harmlessness: Under United States v. Evans, the court found it “highly probable” the errors did not contribute to the conviction because of strong circumstantial evidence (texts about obtaining guns, photos of 9mm pistols matching the casings, location data, post-shooting calls/texts, and clothing linking McCullough to the shooter), plus curative instructions and juror access to the videos.
  • Sentencing affirmed: The court upheld the cross-reference from U.S.S.G. § 2K2.1 through § 2X1.1 to § 2A2.1 (attempted murder), plus a serious-bodily-injury enhancement under § 2A2.1(b)(1)(B). It rejected arguments tied to jurisdictional limits of the federal murder statute, emphasizing that the pertinent Guidelines provisions are not limited to federal crimes and relying on New Jersey law.

III. Analysis

A. Precedents Cited

1. Harmless error and improper law-enforcement lay opinions: United States v. Evans

The panel treated United States v. Evans, 175 F.4th 443 (3d Cir. 2026) as both warning and constraint. It noted that this was the second Rule 701 problem “in less than three months” involving the same U.S. Attorney’s Office, but emphasized it was “duty-bound by precedent” to apply Evans’s harmless-error framework: whether it is “highly probable” the errors did not contribute to the conviction. That standard drove the outcome—recognizing error yet affirming.

2. Rule 403 deference and limits: United States v. Heatherly, United States v. Long, and United States v. Savage

United States v. Heatherly, 985 F.3d 254 (3d Cir. 2021) supplied the baseline principle of broad deference to district courts applying Rule 403. The panel then relied on United States v. Long, 92 F.4th 481 (3d Cir. 2024) to distinguish “prejudice” from “unfair prejudice”—a key move because all inculpatory evidence is prejudicial, but only unfair prejudice triggers exclusion.

The panel found the photos crossed the line by invoking United States v. Savage, 85 F.4th 102 (3d Cir. 2023): the images were the kind of proof that “inhibits neutral application of principles of law to the facts as found.” That framing matters because it characterizes the photos’ effect as distorting deliberation rather than merely strengthening the prosecution.

3. Distinguishing “blood evidence” cases: United States v. Flenoid and Government of Virgin Islands v. Albert

The government leaned on United States v. Flenoid, 415 F.3d 974 (8th Cir. 2005), but the panel distinguished it sharply: in Flenoid the “bloody fingerprints” bore directly on possession under § 922(g)(1), and a limiting instruction was given. Here, the blood photos did not depict ammunition and were “extremely attenuated” from the charged ammunition possession.

The government also cited Government of Virgin Islands v. Albert, 241 F.3d 344 (3d Cir. 2001), which the panel found inapposite because Albert involved a first-degree felony murder charge—making graphic evidence more intrinsically tied to an element of the crime. The contrast underscored the panel’s theme: the government tried to try a shooting/homicide narrative without charging it.

4. Video identification and “helpfulness”: United States v. Fulton and United States v. Valentin

In rejecting the detective’s identification opinion, the panel drew a line consistent with United States v. Fulton, 837 F.3d 281 (3d Cir. 2016), which found error where witnesses lacked “sufficient familiarity” with the defendant’s appearance. The panel contrasted United States v. Valentin, 118 F.4th 579 (3d Cir. 2024), where the witness had seen the defendant “more than fifty times.”

This pairing highlights the operative distinction: a lay identification opinion is most defensible when the witness has real-world familiarity the jury lacks, not when the witness simply reviewed investigative materials and offers a conclusion the jury can reach unaided.

5. Standards of review and sentencing: United States v. Newkirk; state-law references including State v. Gilliam

The court cited United States v. Newkirk, 174 F.4th 336 (3d Cir. 2026) for abuse-of-discretion review of procedural sentencing claims. On the attempted-murder cross-reference, it invoked New Jersey statutes and State v. Gilliam, 541 A.2d 309 (N.J. App. Div. 1988) as part of rejecting a “specific-intent” based challenge under New Jersey law (as the panel characterized that law).

B. Legal Reasoning

1. Rule 403: when “investigation narrative” cannot justify graphic proof

The panel’s Rule 403 analysis is built on two related propositions: (i) the government’s “how the investigation proceeded” rationale does not automatically create probative value sufficient to overcome prejudice, and (ii) the probative link must be to the elements actually at issue—in this case, ammunition possession under § 922(g)(1).

The opinion treated the blood photos as a “mid-trial gore montage” that did not meaningfully advance a disputed fact tied to ammunition. Indeed, the government’s claim that there was no photo showing both “bullets and the blood” became, in the panel’s view, a confession of attenuation: the inflammatory images were not anchored to the charged conduct.

2. Rule 701: “perception” and “helpfulness” are not satisfied by reviewing many videos

The detective’s identification opinion failed two Rule 701 requirements:

  • Perception (Rule 701(a)): The detective lacked a first-hand foundation—no meaningful pre-charge interactions with McCullough— and attempted to bootstrap perception by repeatedly watching surveillance footage and a live feed. The panel called this “fatally circular.”
  • Helpfulness (Rule 701(b)): The opinion was not “helpful” because jurors could compare the video evidence themselves. The panel rejected the notion that “sheer volume” of video makes an officer’s conclusion admissible; Rule 701 does not permit “shortcuts” that replace jury evaluation with law-enforcement “imprimatur.”

3. Harmless error: strong circumstantial proof plus safeguards

Applying Evans, the panel affirmed because the record contained substantial circumstantial evidence connecting McCullough to the ammunition and shooting (texts about acquiring a gun; photos of 9mm pistols matching the casings; cell-site/location data near the scene; post-shooting calls and gun-related text; recovery of clothing matching the shooter; a phone photo of McCullough wearing the hat).

The panel also relied on trial-level safeguards: an instruction that it was the jurors’ “job to decide whether or not Mr. McCullough is in the video,” juror access to the videos during deliberations, final instructions characterizing the detective’s statement as “personal opinion,” and the admonition that law enforcement testimony is not entitled to greater weight.

4. Sentencing: cross-referencing to attempted murder in a § 922(g) ammunition case

The opinion confirms the breadth of the Guidelines’ cross-reference mechanism in firearms/ammunition cases. Starting from U.S.S.G. § 2K2.1, the District Court moved through § 2K2.1(c)(1)(A) and § 2X1.1(a) to § 2A2.1(a), finding by a preponderance that McCullough’s conduct amounted to attempted murder, then applying a serious-bodily-injury enhancement under § 2A2.1(b)(1)(B).

The panel rejected the argument that the federal murder statute’s jurisdictional limits mattered, stating the relevant Guidelines provisions are not limited to federal crimes and that New Jersey murder/attempt standards sufficed for the cross-reference. It also approved reliance at sentencing on evidence that was inadmissible at trial (the opinion describes the blood evidence as “fair game” at sentencing).

C. Impact

  • Trial practice (Rule 403): The decision is a caution that prosecutors cannot justify inflammatory “violent-crime” visuals in a § 922(g)(1) ammunition case merely by claiming they “complete the story” of the investigation. The probative connection to the charged elements remains central.
  • Trial practice (Rule 701): The opinion reinforces that law-enforcement video identification is vulnerable when it is based on investigative review rather than personal familiarity. “More video” does not equal a better Rule 701 foundation.
  • Appellate outcomes: Even where evidentiary errors are clear, Evans-style harmless-error analysis can make reversal difficult if independent circumstantial evidence is robust and the jury is given tools (instructions, access to video exhibits) to make its own determinations.
  • Sentencing leverage: The affirmed cross-reference illustrates how a § 922(g)(1) conviction can effectively be sentenced as a serious violent offense (here, attempted murder) based on judicial factfinding by a preponderance, even when the jury did not try—and the government did not charge— attempted murder.

IV. Complex Concepts Simplified

  • Rule 403 (unfair prejudice): Courts can exclude relevant evidence if its risk of provoking an emotional or improper reaction substantially outweighs its value in proving a fact that matters to the charged offense.
  • Rule 701 (lay opinion): A non-expert witness may give an opinion only if it is based on the witness’s own perception and genuinely helps the jury (not merely by stating a conclusion the jury can reach as well).
  • Harmless error: An appellate court can affirm despite trial error if it is “highly probable” the error did not affect the verdict.
  • Guidelines cross-reference: Some Guidelines provisions instruct courts to sentence based on “another offense” tied to the conduct (e.g., attempted murder) even if the conviction is for a different crime (e.g., ammunition possession).
  • Preponderance of the evidence (sentencing): At sentencing, a judge generally may find facts under a “more likely than not” standard, which is lower than “beyond a reasonable doubt.”
  • Statutory maximum and U.S.S.G. § 5G1.1(a): If the calculated Guidelines range exceeds the statutory maximum, the maximum becomes the effective top of the Guidelines sentence.

V. Conclusion

United States v. Lamar McCullough condemns two common forms of “charge inflation by evidence”: graphic blood imagery with little connection to the charged § 922(g)(1) ammunition offense (Rule 403) and law-enforcement “identification” opinions that rest on investigative review rather than true perceptual familiarity (Rule 701). Yet it simultaneously illustrates the resilience of convictions under rigorous harmless-error review when the record contains strong independent circumstantial proof and jurors are equipped to assess video evidence themselves.

On sentencing, the opinion underscores the practical reach of the firearms Guideline cross-references: a § 922(g)(1) case can be sentenced using an attempted-murder framework grounded in state-law concepts and judicial factfinding, even where the trial itself should not be converted into an uncharged attempted-murder prosecution through inadmissible or unfairly prejudicial evidence.