Introduction

In People of Michigan v. Michael David Zeller, the Michigan Supreme Court denied leave to appeal from a Court of Appeals decision affirming the denial of a motion to suppress evidence obtained during a traffic stop and ensuing canine sniff. Although the Court’s order is non-precedential as to the denial itself, two concurrences deliver consequential guidance on modern Fourth Amendment practice in Michigan: Justice Welch’s concurrence underscores the implications of Michigan’s adult-use marijuana framework (the Michigan Regulation and Taxation of Marihuana Act, “MRTMA”) for canine sniffs, while Justice Bolden’s concurrence clarifies that the Court of Appeals’ 2008 decision in People v. Jones is no longer good law after Florida v. Jardines (2013).

The case centers on whether officers had probable cause to search, given a driver’s tip about a passenger possessing methamphetamine, multiple traffic violations, and an alert by a drug-sniffing dog that was trained to detect, among other substances, marijuana. The concurrences explain how marijuana legalization affects probable cause determinations and cabin the use of older Michigan precedent concerning canine sniffs at a home.

Summary of the Opinion

The Supreme Court of Michigan denied the defendant’s application for leave to appeal, concluding that review was unwarranted. Justice Welch concurred to emphasize that, after MRTMA and the Court’s recent decision in People v. Armstrong, the mere odor of marijuana—standing alone—cannot establish probable cause to search a vehicle. She agreed that, in this case, the totality of the circumstances nevertheless supplied probable cause. Justice Bolden concurred to highlight that People v. Jones (2008), which had upheld a canine sniff at a home’s threshold as non-search activity, was abrogated by Florida v. Jardines (2013). She also reaffirmed that canine sniffs in the vehicular context are governed by Illinois v. Caballes (2005) and Rodriguez v. United States (2015).

Factual and Procedural Background

Officers stopped a car for an obscured license plate. They discovered the driver lacked a license, the vehicle was uninsured, and the driver reported that a passenger was likely carrying methamphetamine. A trained narcotics-detection dog twice alerted to the presence of drugs. Officers ultimately found methamphetamine on defendant Michael David Zeller, who also resisted when officers attempted to handcuff him. The trial court denied a motion to suppress, the jury convicted Zeller of delivery/manufacture of methamphetamine (MCL 333.7401(2)(b)(i)) and two counts of resisting or obstructing a police officer (MCL 750.81d(1)), and the Court of Appeals affirmed. The Michigan Supreme Court denied leave.

Detailed Analysis

Precedents Cited and Their Role

• People v. Armstrong (Mich. 2025): Sets the standard of review (clear error for factual findings; de novo for Fourth Amendment questions) and holds that the smell of marijuana alone is insufficient to establish probable cause to search a vehicle in light of MRTMA.
• People v. Lucynski, 509 Mich 618 (2022): Reaffirms the presumption that warrantless searches are unreasonable absent a recognized exception.
• Pennsylvania v. Labron, 518 US 938 (1996): Articulates the automobile exception—if a vehicle is readily mobile and officers have probable cause to believe it contains contraband, they may search without a warrant.
• People v. Hellstrom, 264 Mich App 187 (2004): Supports the proposition that, on these facts, probable cause extended to searching the passengers, given the totality of circumstances.
• Florida v. Jardines, 569 US 1 (2013): Holds that using a trained police dog to investigate a home and its curtilage is a search under the Fourth Amendment.
• People v. Jones, 279 Mich App 86 (2008): Previously held that a dog sniff from a lawful vantage point outside the home was not a search. Justice Bolden explains this holding is no longer valid after Jardines.
• People v. Gillam, 479 Mich 253 (2007): Confirms that Michigan courts are bound by United States Supreme Court interpretations of federal law.
• Illinois v. Caballes, 543 US 405 (2005): Establishes that a canine sniff conducted during a lawful traffic stop does not generally implicate legitimate privacy interests, so long as it reveals only contraband.
• Rodriguez v. United States, 575 US 348 (2015): Limits Caballes by prohibiting prolongation of a traffic stop to conduct a dog sniff absent reasonable suspicion of criminal activity.
• United States v. Place, 462 US 696 (1983): Early articulation that a well-trained dog sniff is sui generis when it reveals only the presence of contraband.

Legal Reasoning Applied to the Facts

The concurrence by Justice Welch aligns the case with familiar Fourth Amendment doctrine:

• Warrantless searches are presumptively unreasonable (Lucynski) unless an exception applies. The automobile exception applies when a vehicle is readily mobile and there is probable cause to believe it contains contraband (Labron).
• Here, probable cause was established under the totality of the circumstances: the driver’s lack of a license, the vehicle’s lapsed insurance, the driver’s contemporaneous statement that a passenger had methamphetamine, and the canine’s drug alerts. Together, these facts justified a search of the passengers (Hellstrom).
• Armstrong complicates reliance on marijuana indicators: the odor of marijuana alone is not sufficient probable cause to search a vehicle because MRTMA legalizes certain marijuana possession and transport. However, the canine alert here occurred in a setting with additional incriminating factors and a tip specifically about methamphetamine; thus, Armstrong did not require suppression.
• Justice Bolden clarifies that, while canine sniffs at vehicles remain governed by Caballes and Rodriguez, canine sniffs at a home’s front door are searches under Jardines, rendering Jones’s contrary holding obsolete. On these facts, the stop was not argued to be unreasonably prolonged under Rodriguez, and the use of the dog during the stop was permissible under Caballes.

How Armstrong and MRTMA Intersect with Canine Alerts

The critical insight from Justice Welch is that, post-MRTMA, canine alerts cannot be treated as monolithic. If a dog is trained to detect marijuana along with other controlled substances, an “alert” may be ambiguous: is it signaling contraband (e.g., methamphetamine) or lawful marijuana possessed or transported in compliance with MRTMA (e.g., up to 15 grams in a vehicle by an adult 21+)? When a human officer’s detection of marijuana odor alone is insufficient for probable cause, it follows that a canine alert, if attributable only to marijuana, likewise cannot justify a search. The practical problem is that officers may not know what substance triggered the alert.

Zeller does not resolve that question because probable cause arose from multiple reinforcing facts—the driver’s tip about methamphetamine and the totality of the stop—such that the canine alert was not the sole or even necessary pillar of probable cause. Still, the concurrence signals likely litigation ahead: courts may need to inquire into a canine’s training and whether its alerts can reliably be disentangled from now-lawful marijuana, especially where the alert is the primary basis for probable cause.

The Demise of People v. Jones and the Home–Vehicle Divide

Justice Bolden’s concurrence performs an important cleanup function in Michigan Fourth Amendment law:

• People v. Jones (2008) held that a canine sniff at a home’s threshold was not a search because it purportedly exposed only contraband. Florida v. Jardines (2013) rejected that reasoning, holding that bringing a trained dog to a home’s porch is a search requiring a warrant or an exception, because the porch is part of the home’s curtilage and officers exceed the scope of the implied license when they physically intrude to gather evidence.
• Because Michigan courts are bound by the U.S. Supreme Court on federal constitutional questions (Gillam), Jones’s core holding is no longer good law.
• The vehicular context is different. Under Caballes, a canine sniff during a lawful traffic stop generally does not implicate privacy interests, provided it does not detect lawful items. Rodriguez adds that officers may not prolong a stop solely to conduct a dog sniff absent reasonable suspicion. In Zeller, there is no claim of improper prolongation.

Impact and Forward-Looking Considerations

While Zeller is a denial of leave, the concurrences collectively furnish guidance that will shape litigation and police practices:

• Canine training and deployment:
  • Agencies may face pressure to deploy dogs not trained to alert to marijuana, or to document training and alert protocols capable of distinguishing marijuana from other substances, to preserve the probative value of alerts where marijuana is lawfully present.
  • Prosecutors should be prepared to lay a foundation regarding a dog’s training, certification, and target odors, particularly where the alert is central to probable cause.
  • Defense counsel will likely probe whether an alert could be consistent with lawful marijuana possession under MRTMA and whether additional facts tie the alert to contraband beyond marijuana.
• Totals vs. components in probable cause:
  • Post-MRTMA, the “odor of marijuana” factor loses independent weight. Courts will look to other corroborating facts—tips specifying non-marijuana contraband, furtive behavior, admissions, visible contraband, or other objective indicators.
• Home–vehicle distinction:
  • Jones should not be cited for canine sniffs at residences; Jardines controls. Warrantless canine sniffs at a home’s door or curtilage are searches and presumptively unlawful absent an exception.
  • For vehicles, Caballes and Rodriguez remain the baseline framework.
• Scope of searches of persons vs. vehicles:
  • Zeller affirms that, under the specific totality here (including a tip about methamphetamine and two dog alerts), officers had probable cause to search passengers. Trial courts should be careful to ensure that probable cause is particularized when searching a person, as opposed to containers or the vehicle generally.

Complex Concepts Simplified

• Automobile exception: Police may search a readily mobile vehicle without a warrant if they have probable cause to believe it contains contraband (Labron). No separate exigency is required beyond mobility and probable cause.
• Probable cause vs. reasonable suspicion:
  • Probable cause is a fair probability that evidence of a crime will be found in a particular place.
  • Reasonable suspicion is a lower standard allowing a brief investigative stop but not a search.
  • Rodriguez uses reasonable suspicion as the threshold to extend a traffic stop for a dog sniff beyond the time needed to handle the traffic matter.
• Totality of the circumstances: Courts do not parse facts in isolation; they aggregate the objective facts known to officers to decide whether probable cause exists.
• Curtilage: The area immediately surrounding and associated with the home enjoys the same Fourth Amendment protection as the home. Entering the curtilage to conduct a canine sniff is a search (Jardines).
• MRTMA’s effect on probable cause: Because adults 21+ may lawfully possess and transport limited amounts of marijuana (e.g., up to 15 grams in a vehicle), the smell of marijuana alone no longer reliably indicates criminal activity. Armstrong holds the odor alone is insufficient to justify a vehicle search.
• Canine alerts post-legalization: If a dog is trained to alert to marijuana, an alert could indicate lawful possession. Without more, that ambiguity may undercut probable cause.

Practical Guidance

For Law Enforcement

• During traffic stops, ensure the stop remains within its mission (documents, registration, insurance, safety tasks). Do not prolong the stop for a canine sniff absent reasonable suspicion (Rodriguez).
• When relying on a canine alert, document:
  • Training and certification (including whether the dog alerts to marijuana).
  • The sequence of events (to show no Rodriguez violation).
  • Other corroborating facts beyond marijuana odor, especially specific information indicating non-marijuana contraband.
• Do not deploy canine sniffs at a home’s front door or curtilage without a warrant or a valid exception; Jardines treats this as a search.

For Prosecutors

• Anticipate Armstrong-based challenges. Be prepared to show that probable cause flowed from factors other than marijuana odor—e.g., tips specifying other narcotics, admissions, or visible contraband.
• Establish through testimony whether the dog is trained to alert to marijuana and, if so, how the alert was corroborated or tethered to non-marijuana contraband.
• Avoid reliance on People v. Jones for residential canine sniffs; cite Jardines, Caballes, and Rodriguez appropriately.

For Defense Counsel

• Probe the dog’s training history, target odors, false alert rate, and whether the alert could be consistent with lawful MRTMA conduct.
• Challenge the stop’s duration and scope under Rodriguez; scrutinize whether the sniff prolonged the stop absent reasonable suspicion.
• Distinguish between probable cause to search a vehicle or container and probable cause to search a person; insist on particularized probable cause for personal searches.

For Trial Courts

• Make explicit findings about the canine’s training and the presence (or absence) of marijuana among target odors, especially where the dog alert is central to probable cause.
• Apply Armstrong to discount marijuana odor as a standalone basis for probable cause; require corroborating facts when marijuana could explain the alert.
• Treat Jones as abrogated by Jardines in cases involving residential canine sniffs.

Conclusion

The Michigan Supreme Court’s denial of leave in Zeller leaves the Court of Appeals’ affirmance intact, but the concurrences perform important doctrinal work:

• Post-MRTMA and Armstrong, marijuana odor alone cannot furnish probable cause to search a vehicle. Canine alerts are correspondingly less probative when a dog is trained to detect marijuana, unless corroborated by other facts.
• People v. Jones’s approval of canine sniffs at the threshold of a home is no longer viable; Florida v. Jardines controls and treats such conduct as a search.
• In the vehicular context, Caballes and Rodriguez continue to govern: a canine sniff during a lawful stop is permissible, but the stop cannot be extended for the sniff absent reasonable suspicion.
• On these facts, the amalgam of the driver’s tip about methamphetamine, driving-related violations, and two canine alerts established probable cause under the totality of the circumstances to search the passengers, leading to the lawful discovery of methamphetamine on Zeller.

Zeller thus serves as a cautionary and clarifying decision for Michigan’s Fourth Amendment practice in the legalization era: canine sniffs remain valuable investigative tools, but their evidentiary weight must be carefully calibrated to the realities of lawful marijuana possession, and residential deployments must conform to Jardines. Expect future litigation to refine how Michigan courts evaluate canine alerts when marijuana is among the dog’s target odors and when the alert is the primary basis for probable cause.