B. Legal Reasoning
(i) Standing and abandonment: the timing rule does the heavy lifting
The panel’s most concrete doctrinal move is its correction of the district court’s standing analysis. The district court treated Duran’s later on-scene disclaimer (“I don’t have a bag,” “no” checked bags) as eliminating standing across the board, and it “ignored the timing of Duran’s disavowal.” The Fourth Circuit held that approach conflicts with United States v. Smith, which requires assessing standing “at the time of the search.”
Applying that timing principle:
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Second suitcase: Duran disclaimed ownership before it was searched. Under United States v. Ferebee, that amounts to abandonment; abandonment destroys a reasonable expectation of privacy; therefore, no standing.
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First suitcase: It was searched before any disclaimer. At that time, there was no abandonment evidence. The government—bearing the burden to justify the warrantless search—could not use a later disclaimer to retroactively defeat standing. The district court’s contrary finding was “against the clear weight of the evidence” (invoking United States v. Mayberry).
Notably, the panel also grounded standing in the government’s own proof linking Duran to the suitcases (surveillance footage of him loading them). That evidence supported an “ownership or possessory interest” and therefore a legitimate expectation of privacy under United States v. Castellanos and Bond v. United States.
(ii) Merits: extending (or at least applying) the automobile exception logic to buses
The opinion states the Fourth Circuit had “not explicitly determined” that the automobile exception applies to buses, but then reasons that the exception’s justifications—mobility and reduced privacy expectations in heavily regulated vehicles—apply “with equal, if not greater, force to buses.” It also aligns with sister-circuit authority (United States v. Tuton; United States v. Pina).
The functional consequence is clear: if probable cause exists, officers may conduct a warrantless search of a bus’s relevant compartments and containers that might conceal contraband, consistent with Pennsylvania v. Labron, United States v. Ross, California v. Acevedo, and United States v. Kelly.
(iii) Probable cause from a “non-final” dog alert: deference + Harris framework
Duran’s core suppression argument was that Kaos did not give a final trained “sit” response and thus did not reliably alert. The panel treated “whether Kaos alerted” as a fact question and deferred to the district court’s credibility findings under United States v. Patiutka.
Under Florida v. Harris, the court emphasized controlled-setting evidence: Kaos was certified in 2020, recertified annually, and had training records indicating 100% accuracy in a controlled environment. The district court also considered field deployments (14 positive alerts out of 19 deployments), though Harris warns field results can be a less reliable metric. The panel concluded this record was “robust” enough to support finding reliability and probable cause.
The panel also relied on United States v. Kelly to reject any suggestion that an alert must pinpoint the precise suitcase: probable cause is not “so exacting” that it requires a dog to locate drugs within a foot or two, especially in a confined luggage-hold area.
(iv) Built-in limiting principle: no “unbounded authority”
While affirming, the court acknowledged the defense expert’s cueing argument and the possibility a court could find such an alert unreliable on a different record. It also cited United States v. Tuton to stress that a general alert does not authorize indiscriminate searching of “hundreds of bags” without considering the totality of the circumstances. This signals that the holding is not a blanket rule, but a fact-sensitive application of Harris.