Wyoming Rule: Unraised K9 Free-Air Sniff Challenges Are Waived Absent “Impediment”-Based Good Cause; Coded Drug Messages Admissible as 404(b) Context for Intent to Distribute

Introduction

In Marvin Emmett Brown, Jr. v. The State of Wyoming, 2026 WY 96 (Sept. 1, 2026), the Wyoming Supreme Court affirmed multiple drug and firearm-related convictions arising from a “wall stop” traffic stop that led to a K9 free-air sniff, a vehicle search, and a subsequent search warrant for Mr. Brown’s home. The appeal presented two central issues: (1) whether Mr. Brown could challenge the validity of the K9 alert when he did not timely raise that suppression theory in a pretrial motion, and (2) whether the district court abused its discretion by admitting coded text and Facebook messages under W.R.E. 404(b).

The parties were Marvin Emmett Brown, Jr. (Appellant/Defendant) and The State of Wyoming (Appellee/Plaintiff). The decision is particularly important for its reinforcement of Wyoming’s procedural waiver doctrine in suppression litigation and its application of Wyoming’s structured 404(b) framework to coded communications offered to show intent to distribute and to place charged conduct in context.

Summary of the Opinion

  • Suppression/waiver: Mr. Brown waived any challenge to the K9 free-air sniff alert’s validity because he did not raise it in his initial suppression motion and never filed a supplemental/second motion. He also failed to show good cause under W.R.Cr.P. 12(g), because the record showed no “impediment” to raising the issue earlier.
  • Rule 404(b): The district court did not abuse its discretion by admitting Mr. Brown’s coded text and Facebook messages with five individuals. The messages were properly admitted to provide history/context and to support the inference of intent to distribute (rather than propensity), and the probative value was not substantially outweighed by unfair prejudice.

Analysis

Precedents Cited

A. Waiver and “Good Cause” for Untimely Suppression Theories

The Court’s waiver holding is built on a line of Wyoming cases interpreting W.R.Cr.P. 12:

  • Keller v. State, 2024 WY 72, ¶ 37, 551 P.3d 465, 477 (Wyo. 2024): Cited for the governing rule that suppression motions must be made before trial under W.R.Cr.P. 12(b)(3), that failure generally waives appellate review, and that waiver is reviewed de novo when the record is clear. The Court uses Keller to frame both the procedural requirement and the standard of review.
  • Rodriguez v. State, 2019 WY 25, ¶ 16, 435 P.3d 399, 403 (Wyo. 2019): Used (via Keller) for de novo review when waiver facts are undisputed, and—critically—cited at ¶ 39 for the appellate posture when good cause was not meaningfully developed below. The Court invokes Rodriguez to ask whether the district court would have abused its discretion had it found no good cause.
  • Herrera v. State, 2019 WY 93, ¶ 18, 448 P.3d 844, 849 (Wyo. 2019): Supplies the “impediment” formulation: good cause is not shown if the record reveals no impediment to raising the issue earlier. The Court uses Herrera as the yardstick and then concludes the record shows none.
  • Mathewson v. State, 2019 WY 36, ¶ 41, 438 P.3d 189, 205 (Wyo. 2019): Cited for the related rule that even when a defendant files a suppression motion, a new suppression argument raised for the first time on appeal is barred absent good cause under W.R.Cr.P. 12(g).
  • United States v. Daniels, 803 F.3d 335, 352 (7th Cir. 2015): Cited through Rodriguez for the analytic approach to good-cause review where the defendant did not develop good cause in the trial court. The Wyoming Supreme Court uses it to support asking whether a no-good-cause ruling would have been within the district court’s discretion.
  • United States v. Walden, 625 F.3d 961, 966 (6th Cir. 2010): Supports rejecting “new counsel” as good cause where substitution occurs with time remaining before deadlines. The Court analogizes: the mere fact of attorney substitution does not itself establish an impediment.

B. Rule 404(b) Framework, Relevance, and Rule 403 Balancing

For the 404(b) evidentiary ruling, the Court anchors its review in well-developed Wyoming doctrine:

  • King v. State, 2023 WY 36, ¶ 26, 527 P.3d 1229, 1240 (Wyo. 2023): Establishes abuse-of-discretion review when the defendant makes a pretrial 404(b) demand for notice.
  • Mayhew v. State, 2019 WY 38, ¶ 23, 438 P.3d 617, 623 (Wyo. 2019): Supplies the “considerable deference” language and places the burden on the appellant to show abuse of discretion.
  • Garrison v. State, 2018 WY 9, ¶ 27, 409 P.3d 1209, 1217 (Wyo. 2018): Provides the recognized category that other-acts evidence may be admitted if it “forms part of the history of the event or serves to enhance the natural development of the facts”—the contextual or narrative exception the Court relies on to uphold admission of the messages. It is also cited (¶ 30) for the Rule 403 prejudice articulation (quoting Law v. State).
  • Anderson v. State, 2022 WY 119, ¶¶ 13–15, 25, 517 P.3d 583, 588–91 (Wyo. 2022): Restates the mandatory four-part procedure (proper purpose, relevance, Rule 403 balancing, limiting instruction on request), plus the multi-factor probative/prejudice framework. Also supports the proposition that juries are entitled to have offenses placed in context because “events do not occur in a vacuum” (quoting Garrison v. State).
  • Barrett v. State, 2022 WY 64, ¶¶ 45, 48, 509 P.3d 940, 949-50 (Wyo. 2022): Cited through Anderson regarding the required framework and the “legitimate basis” threshold on appeal.
  • Gleason v. State, 2002 WY 161, ¶ 28, 57 P.3d 332, 343 (Wyo. 2002): Supports that express findings on each factor are not required so long as the record shows the court conducted the required analysis.
  • United States v. Hardwell, 80 F.3d 1471, 1488 (10th Cir. 1996): Used for the principle that failure to expressly identify the proper 404(b) purpose can be harmless if the purpose is apparent from the record and admission is correct.
  • Hill v. State, 2016 WY 27, ¶ 30, 371 P.3d 553, 562 (Wyo. 2016): Reaffirms the broad relevance concept: evidence tends to be relevant if it proves or disproves an element of the charged crime.
  • Santistevan v. State, 2024 WY 17, ¶ 19, 542 P.3d 200, 206 (Wyo. 2024): Supports admitting other-acts evidence not merely as “course of conduct,” but also to show an ongoing scheme or plan. The Court uses this to validate treating the coded messages as indicative of ongoing distribution activity.
  • Hart v. State, 2002 WY 163, ¶ 22, 57 P.3d 348, 356 (Wyo. 2002): Cited for the proposition that Rule 404(b) has no specific time limit; remoteness is a factor, not a bar.
  • Law v. State, 2004 WY 111, ¶ 15, 98 P.3d 181, 187 (Wyo. 2004): Appears via Garrison v. State for the burden to show minimal probative value and extreme inflammatory effect when claiming undue prejudice.

Legal Reasoning

1) Waiver of a K9 Free-Air Sniff Challenge Under W.R.Cr.P. 12

The Court treated the K9 issue as a classic Rule 12 problem: suppression theories must be raised before trial, and new theories are waived unless good cause is shown. Mr. Brown’s initial motion attacked the stop’s justification (reasonable suspicion for the traffic stop) but did not challenge the dog’s alert as unreliable or handler-cued. He later expressed interest in litigating the dog sniff, but—critically—never filed a supplemental or second suppression motion.

The Court emphasized two record-driven conclusions:

  1. Waiver was “plainly” established: Because the K9 validity theory was never presented in a motion, it was not preserved for appellate review.
  2. No good cause (“impediment”) existed: The district court found discovery had been provided “at least twice,” and K9 information appeared in charging documents; Mr. Brown observed the sniff in real time; and counsel had already received an extension for the initial suppression filing. Substitution of counsel did not create good cause where discovery existed and time remained. The district court also did not actually deny leave to file; it indicated it would “take a look” if a motion were filed. The failure was ultimately the defense’s non-filing, not an external barrier.

Procedurally, the Court framed the question as whether the district court would have abused its discretion in finding no good cause. Given the absence of a demonstrable impediment, it held the answer was no.

2) Admission of Coded Messages Under W.R.E. 404(b)

The Court upheld admission of messages referencing “groceries,” “parts,” “green chili,” and quantities (“1/2 a beef,” “50”), concluding the district court applied the required 404(b) methodology and had a legitimate basis for admission.

The Court rejected the argument that the messages were admitted solely for propensity, crediting two non-propensity rationales:

  • Context/history (“natural development of the facts”): The messages helped explain the broader narrative of distribution activity, placing the charged possession-with-intent in its setting, consistent with Garrison v. State and Anderson v. State.
  • Intent and agreement to deliver: The messages tended to show Mr. Brown’s intent to distribute and an ongoing scheme/plan rather than mere personal use—facts “of consequence” under W.R.E. 401 and relevant to elements of the charged crimes, consistent with Hill v. State.

On the claimed analytical deficiency (failure to expressly label the “proper purpose”), the Court treated any omission as harmless because the purpose was apparent from the district court’s written order, citing United States v. Hardwell.

On remoteness, the Court reiterated there is no categorical time bar under Hart v. State. Messages spanning late 2023 to September 2024 were within the “same general timeframe,” supporting relevance to an ongoing scheme.

Finally, the Court deferred to the district court’s Rule 403 balancing. It recognized the similarity between the messages and charged conduct can increase prejudice risk, but it also increases probative value when the defense theory is “the drugs were not his” (making intent/knowledge and distribution context highly probative). Under the “legitimate basis” standard from Anderson v. State and Mayhew v. State, this sufficed.

Impact

Suppression Practice in Wyoming: Tightening the Incentives to Litigate Early and Specifically

The decision reinforces a practical rule for Wyoming criminal litigation: a defendant must raise each suppression theory—stop, sniff, search, warrant, etc.—in a timely pretrial motion, or it will be treated as waived. Merely signaling intent to file later, or complaining of late-discovered details, will not establish good cause absent a demonstrated impediment in the record. This encourages:

  • more comprehensive initial suppression motions (including K9 reliability/handler cueing theories when the case hinges on an alert);
  • prompt supplementation once discovery is received; and
  • clear creation of a record on “good cause” if late litigation is genuinely necessary.

404(b) and Digital Evidence: Coded Communications as Context and Proof of Intent

The 404(b) ruling signals continued receptivity to coded texts and social media messages in drug prosecutions when they contextualize the charged conduct and bear on intent to distribute. It also underscores:

  • district courts need not produce a checklist-style factor-by-factor written decision (Gleason v. State), as long as the required framework is applied;
  • contextual evidence may be admitted to explain the sequence of events and “proper setting” (Anderson v. State); and
  • remoteness arguments will usually be treated as weight/relevance factors, not categorical exclusions (Hart v. State).

Complex Concepts Simplified

Free-air sniff
A K9 sniff conducted around the exterior of a vehicle, without entering it. If the dog alerts, officers often argue that alert provides probable cause to search.
Motion to suppress (W.R.Cr.P. 12(b)(3))
A pretrial request asking the court to exclude evidence obtained in violation of constitutional or statutory rules (e.g., illegal stop/search).
Waiver vs. forfeiture
Both can block appellate review. In this case, Mr. Brown withdrew an argument about “forfeiture,” and the Court treated the failure to timely raise the K9 theory as waiver under Rule 12.
Good cause / “impediment” (W.R.Cr.P. 12(g))
An exception allowing relief from waiver when something actually prevented timely filing (for example, truly unavailable information despite diligence). If the record shows the issue could have been raised, good cause is not established.
W.R.E. 404(b)
A rule that generally forbids “other acts” evidence to prove a person’s character/propensity, but allows it for specific non-propensity purposes (intent, knowledge, plan, context/history, etc.).
W.R.E. 403 balancing
Even relevant evidence can be excluded if its probative value is substantially outweighed by unfair prejudice, confusion, or other dangers.
“Course of conduct” / “ongoing scheme”
A way of describing evidence that shows a continuing pattern tied to the charged conduct, used to contextualize events and prove intent or plan rather than bad character.

Conclusion

Brown delivers two clear takeaways. First, suppression litigation in Wyoming is rigorously governed by W.R.Cr.P. 12: if a defendant does not timely present a specific suppression theory—here, the reliability/validity of a K9 free-air sniff alert—appellate review is waived unless the defendant can show good-cause “impediment” in the record. Second, the Court reaffirmed a flexible but structured approach to W.R.E. 404(b): coded digital communications may be admitted to place the charged crime in context and to prove intent to distribute, so long as the district court applies the required framework and reasonably balances probative value against unfair prejudice.