People v. McKnight

          Rehearing Denied July 01, 2019

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          Certiorari to the Colorado Court of Appeals, Court of Appeals Case No. 16CA50

         Attorneys for Petitioner: Philip J. Weiser, Attorney General, Paul Koehler, First Assistant Attorney General, Denver, Colorado

          Attorneys for Respondent: Megan A. Ring, Public Defender, John Plimpton, Deputy Public Defender, Denver, Colorado

         OPINION

         HOOD, JUSTICE

         [¶1] Inside defendant Kevin McKnight’s truck, police officers discovered a pipe containing what later proved to be methamphetamine residue. That discovery culminated in McKnight’s conviction for certain drug offenses. On appeal, he challenged the constitutionality of the search that revealed the pipe.

         [¶2] A division of the court of appeals reversed McKnight’s convictions. People v. McKnight, 2017 COA 93, ¶ 25, __ P.3d __. Each member of the division wrote separately, wrestling with what effect, if any, legalized marijuana in Colorado should have on the constitutionality of the search of McKnight’s truck. To which you might say, but this is a methamphetamine case. So, why are we talking about marijuana? Well, the drug-detection dog used to find the pipe, Kilo, was trained to alert on multiple drugs, including marijuana. Even a hint of marijuana can trigger the same response from Kilo as any quantity of methamphetamine.

         [¶3] And that’s where things get tricky. After all, the possession of an ounce or less of marijuana by someone twenty-one or older is legal in Colorado, following the passage of Amendment 64, Colo. Const. art. XVIII, § 16(3), even though such possession remains illegal under federal law. Thus, no matter how reliable his nose, Kilo can now render a kind of false positive for marijuana. He has been trained to alert to marijuana based on the notion that marijuana is always contraband, when that is no longer true under state law. And historically, whether a drug-detection dog might alert on noncontraband drives whether the dog’s sniff constitutes a search implicating constitutional protections. The dog’s sniff arguably intrudes on a person’s reasonable expectation of privacy in lawful activity. If so, that intrusion must be justified by some degree of particularized suspicion of criminal activity.

         [¶4] Does this mean that Amendment 64 gave McKnight a reasonable expectation of privacy under either the federal or state constitution that was violated by Kilo’s keen sense of smell? McKnight says yes. Among other things, he claims that the Colorado Constitution prohibited Kilo’s intrusion without at least reasonable suspicion that McKnight had committed or was committing a crime. Because there was none, McKnight asserts that the trial court should have suppressed the pipe. Two members of the division agreed. McKnight, ¶ 3.

         [¶5] And even if the "sniff [was] up to snuff" (to use Justice Kagan’s popular shorthand from a slightly different context in Florida v. Harris, 568 U.S. 237, 248, 133 S.Ct. 1050, 185 L.Ed.2d 61 (2013)), McKnight further argued that there was no probable cause for the post-sniff hand search of his truck that revealed the pipe. Again, because of Amendment 64, two members of the division agreed. McKnight, ¶ 4.

         [¶6] The People counter that, despite Amendment 64, marijuana remains contraband in many circumstances at the state level, and illegal under all circumstances federally, and thus Kilo’s sniff was not a search requiring so much as reasonable suspicion. The People further contend that an alert from a dog trained to detect marijuana, in

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addition to other substances, still provides probable cause justifying a search.

         [¶7] We hold that a sniff from a drug-detection dog that is trained to alert to marijuana constitutes a search under article II, section 7 of the Colorado Constitution because that sniff can detect lawful activity, namely the legal possession of up to one ounce of marijuana by adults twenty-one and older. We further hold that, in Colorado, law enforcement officers must have probable cause to believe that an item or area contains a drug in violation of state law before deploying a drug-detection dog that alerts to marijuana for an exploratory sniff. Because there was no such probable cause justifying Kilo’s search of McKnight’s truck, the trial court erred in denying McKnight’s motion to suppress.

         [¶8] Accordingly, we affirm the judgment of the court of appeals.

          I. Facts and Procedural History

         [¶9] Evidence presented at a suppression hearing established the following facts.

         [¶10] While on patrol in an unmarked police vehicle one night in February 2015, Craig Police Officer Bryan Gonzales observed a parked pickup truck facing the wrong way in a one-way alley near an apartment complex. A man stood outside of the passenger-side door of the truck. Although Officer Gonzales saw no behavior consistent with an exchange or transaction, he followed the truck as it traveled a few blocks. The truck then parked in front of a residence where police had found drugs almost two months earlier, and it remained parked there for approximately fifteen minutes. During that time, no one exited the truck or the residence. When the truck started moving again, Gonzales trailed along.

         [¶11] When the driver of the truck failed to signal a turn, Gonzales pulled the truck over. He discovered that McKnight was the driver. And Gonzales recognized the passenger as someone who had used methamphetamine "at some point in the past," but he wasn’t sure how recently.

         [¶12] During the traffic stop, Gonzales asked Sergeant Courtland Folks of the Moffat County Sheriff’s Office to respond with his drug-detection dog, Kilo, who had been trained to detect the odors of marijuana, methamphetamine, cocaine, heroin, and ecstasy. If Kilo detects the scent of any one of those substances, he should alert. And he exhibits the same alert for all five drugs.

         [¶13] Within five minutes of the stop, Kilo was on the job. As Folks walked Kilo around McKnight’s truck, Folks asked McKnight if he had "any narcotics on him." McKnight said no. Kilo quickly "alerted" on the driver’s door beneath the driver’s open window. This means that Kilo engaged in a rapid sniffing pattern and behaved in a manner suggesting the presence of one of the substances on which he had been trained. According to Folks, Kilo then "put his nose on the driver’s door, back to the door handle, did a purge, which means he cleared his nose, took another deep breath and immediately started giving a trained indication, which was barking."

         [¶14] The officers then ordered McKnight and the passenger to exit the truck. After they complied, the officers patted them down and found nothing on them. The officers then searched the truck by hand. In a storage compartment under the rear seat, they found a pipe containing suspected methamphetamine residue.

         [¶15] Before trial, the defense moved to suppress the pipe, arguing that it was the fruit of an unconstitutional search. Specifically, McKnight argued that because marijuana is legal in Colorado and Kilo was trained to detect marijuana, Kilo’s sniff was a search that required particularized suspicion of criminal activity before Kilo could be deployed, and there was no such suspicion on these facts. Moreover, he contended that Kilo’s alert did not provide probable cause for a full-blown, human search of the truck. Through counsel, McKnight grounded his arguments in the search and seizure clauses of both the United States and Colorado Constitutions.

         [¶16] After a hearing, the trial court denied the motion to suppress. In relevant part, the trial court noted that the possession of marijuana remains illegal under many circumstances in Colorado and is categorically illegal

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under federal law. Without explicitly stating as much, the trial court seemed to reason that a sniff by a dog trained to detect marijuana does not constitute a search. And even if Kilo’s sniff was a search, the trial court went on to conclude that there was reasonable suspicion of criminal activity supporting the search. With ample record support, the court also concluded that Kilo reliably sniffs out the drugs on which he’s been trained. The trial court did not address whether there was probable cause for the officers’ hand search of the truck.

         [¶17] A jury later convicted McKnight of possession of a controlled substance and possession of drug paraphernalia.

         [¶18] McKnight appealed. In three separate but partially overlapping opinions, the court of appeals unanimously agreed that the trial court erred in denying McKnight’s motion to suppress the pipe and that the error was not harmless. Therefore, the division reversed McKnight’s convictions.

• Judge Dailey, writing for himself and Judge Berger, agreed with McKnight that, under the Colorado Constitution after the enactment of Amendment 64, Kilo’s sniff was a search requiring reasonable suspicion of criminal activity. McKnight, ¶ 18 ("Because a dog sniff of a vehicle could infringe upon a legitimate expectation of privacy solely under state law, that dog sniff should now be considered a ‘search’ for purposes of article II section 7 of the state constitution where the occupants are twenty-one years or older."). Judge Dailey further determined that the reasonable suspicion standard should govern, and he concluded that the totality of the circumstances did not give the police reasonable suspicion that McKnight had engaged in criminal activity. Id. at ¶¶ 19-20, 22-24.

• Judge Jones, writing for himself and Judge Berger, agreed with McKnight that Kilo’s alert, even in combination with other circumstances, did not give the police probable cause to conduct a warrantless hand search of McKnight’s truck. Id. at ¶¶ 49-54 (Jones, J., specially concurring). In doing so, Judge Jones sidestepped the issue of whether Kilo’s sniff now constitutes a search under state law. Id. at ¶ 37.

• Judge Berger, writing for himself, explained how a person could have an enforceable expectation of privacy in the possession of marijuana under state law, even in the face of a federal prohibition. First, he noted that Colorado courts must give effect to Colorado voters’ enactment of Amendment 64. Id. at ¶ 29 (Berger, J., specially concurring). Second, he observed that the People have not argued that Amendment 64 is preempted by federal law. Id. Finally, he concluded that when Amendment 64 legalized possession of up to one ounce of marijuana for personal use by persons twenty-one years of age or older, it also limited police authority to enforce the federal prohibition. Id. at ¶ 31.

         [¶19] The People filed a petition for a writ of certiorari, and we agreed to review the case.^[1]

          II. Analysis

         [¶20] After identifying the standard of review, we examine the parallel evolution of federal and state jurisprudence concerning police use of drug-detection dogs. We review long-standing law reasoning that a sniff is not a search because an individual has no legitimate expectation of privacy as to contraband. But after the passage of Amendment 64, possession of an ounce or less of marijuana by someone twenty-one or older is legal, and thus, marijuana is no longer always "contraband" under state law. Because Kilo’s sniff could detect lawful activity, we conclude his sniff was a search under the Colorado Constitution. We then consider

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what level of suspicion would justify deploying such a dog to sniff a vehicle, ultimately concluding that, because the sniff is a search, there must be probable cause to believe a vehicle contains illegal narcotics under state law before deploying a drug-detection dog trained to alert to marijuana. We conclude that, under the totality of the circumstances, there was no probable cause justifying the use of Kilo to sniff McKnight’s truck or the subsequent hand search of the truck, and, exclusion of the pipe is the appropriate remedy for this violation of the Colorado Constitution.

          A. Standard of Review

         [¶21] When reviewing a suppression order, we defer to the trial court’s factual findings if the record supports them, but we review de novo the court’s legal conclusions. Grassi v. People, 2014 CO 12, ¶ 11, 320 P.3d 332, 335. So, we address the constitutionality of Kilo’s sniff and the subsequent hand search of the truck de novo.

          B. Federal Law Governing Searches and Drug-Detection Dogs

         [¶22] The Fourth Amendment to the United States Constitution states:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

         It "protects people, not places" from unreasonable governmental searches and seizures. Katz v. United States, 389 U.S. 347, 351, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967); see also U.S. Const. amend. IV. A search in the constitutional sense occurs "when the government violates a subjective expectation of privacy that society recognizes as reasonable." Kyllo v. United States, 533 U.S. 27, 33, 121 S.Ct. 2038, 150 L.Ed.2d 94 (2001) (citing Katz, 389 U.S. at 361, 88 S.Ct. 507 (Harlan, J., concurring)).

         [¶23] "Warrantless searches are presumptively unreasonable," and thus unconstitutional, unless an exception to the warrant requirement exists. United States v. Karo, 468 U.S. 705, 717, 104 S.Ct. 3296, 82 L.Ed.2d 530 (1984). Courts measure the constitutionality of a search (either pursuant to a warrant or warrantless) at the time a search is performed. The Fourth Amendment does not favor post hoc justifications based on what was found during a search. See, e.g., People v. Sotelo, 2014 CO 74, 336 P.3d 188 ("[C]ourts may not use the benefit of hindsight in evaluating application of the Fourth Amendment."); see also California v. Acevedo, 500 U.S. 565, 599, 111 S.Ct. 1982, 114 L.Ed.2d 619 (1991) (Stevens, J., dissenting) ("Neither evidence uncovered in the course of a search nor the scope of the search conducted can be used to provide post hoc justification for a search unsupported by probable cause at its inception."); United States v. Montoya de Hernandez, 473 U.S. 531, 559, 105 S.Ct. 3304, 87 L.Ed.2d 381 (1985) (Brennan, J., dissenting) ("[P]ost hoc rationalizations have no place in our Fourth Amendment jurisprudence, which demands that we ‘prevent hindsight from coloring the evaluation of the reasonableness of a search or seizure.’ " (quoting United States v. Martinez-Fuerta, 428 U.S. 543, 565, 96 S.Ct. 3074, 49 L.Ed.2d 1116 (1976))).

         [¶24] A warrantless search may be constitutional if there was probable cause to believe the place or item to be searched contained contraband or evidence of a crime, and the circumstances met an exception to the warrant requirement. One such exception is the automobile exception. Beginning with Carroll v. United States, the Supreme Court has reasoned that automobiles warrant a lesser degree of privacy than that afforded to homes because of a vehicle’s "ready" mobility, the existing, pervasive government regulation of cars, and the low probability that a car is used to store personal effects. See 267 U.S. 132, 153, 45 S.Ct. 280, 69 L.Ed. 543 (1925) (reasoning that there is "a necessary difference between a search of a store, dwelling house, or other structure ... [where] a proper official warrant readily may be obtained and a search of a ship, motor boat, wagon, or automobile ... where it is not practicable to secure a warrant, because the

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vehicle can be quickly moved"). Nearly a century later, the law remains the same: If an officer has lawfully stopped a vehicle, and has probable cause to believe the vehicle contains evidence of a crime, then the officer may conduct a search of the car without first obtaining a warrant. Collins v. Virginia, __ U.S. __, 138 S.Ct. 1663, 1670, 201 L.Ed.2d 9 (2018).

         [¶25] As the Supreme Court continued to embrace and refine the automobile exception, drug-detection dogs scampered on to the scene. United States v. Place marked the Supreme Court’s first foray into this area of the law. 462 U.S. 696, 103 S.Ct. 2637, 77 L.Ed.2d 110 (1983). In Place, two law enforcement officers grew suspicious that Place might be carrying narcotics after observing him at Miami International Airport. Id. at 698, 103 S.Ct. 2637. The officers remained suspicious after talking with the defendant, though they ultimately decided not to search his luggage. Id. The officers looked closely at the luggage tags on the defendant’s checked bags and noticed discrepancies between the two addresses and the phone number the defendant gave the airline. Id. The officers notified law enforcement agents in New York of the defendant’s impending arrival. Id. Two Drug Enforcement Administration agents contacted the defendant when he landed, informed the defendant that they believed he may be transporting illegal narcotics, and ultimately seized his luggage in order to subject it to a sniff from a drug-detection dog. Id. at 698-99, 103 S.Ct. 2637.

         [¶26] Though Place turned on whether the seizure of the defendant’s luggage without probable cause violated the Fourth Amendment, the Court discussed the use of drug-detection dogs at airports to sniff luggage suspected of containing illegal narcotics. See id. at 707, 103 S.Ct. 2637. The Court reasoned that exposing "temporarily detain[ed] personal luggage" to a dog trained to detect narcotics wasn’t a search under the Fourth Amendment. Id. at 697-98, 103 S.Ct. 2637. The sniff is "sui generis," stated the Court, because it is less intrusive than other search techniques and it can only reveal the "presence or absence of narcotics, a contraband item." Id. at 707, 103 S.Ct. 2637. The Court’s rationale thus hinged on two notions: (1) A dog sniff is a minimally intrusive tactic (2) that can only reveal whether or not contraband is present in the luggage. Beyond that, the sniff reveals nothing. Despite the narrow circumstances in which the Court made these statements, they have formed the foundation for much federal (and state) jurisprudence on dog sniffs.

         [¶27] The Supreme Court relied on this reasoning in Illinois v. Caballes to conclude that "the use of a well-trained narcotics-detection dog— one that ‘does not expose noncontraband items that otherwise would remain hidden from public view’— during a lawful traffic stop, generally does not implicate legitimate privacy interests." 543 U.S. 405, 409, 125 S.Ct. 834, 160 L.Ed.2d 842 (2005) (internal citation omitted) (quoting Place, 462 U.S. at 707, 103 S.Ct. 2637). In Caballes, an officer led a drug-detection dog around a vehicle that was lawfully stopped for speeding. Id. at 406, 125 S.Ct. 834. The dog alerted at the trunk, leading to a search that revealed marijuana. Id. Looking back to Place, the Court rejected the claim that the dog sniff was unconstitutional because there was no reasonable suspicion that the defendant possessed narcotics when he was initially stopped. Id. at 408-09, 125 S.Ct. 834. Notably, the Court didn’t focus on how the officers in Place had already grown suspicious that the defendant was engaged in illegal narcotics activity before stopping and contacting the defendant. Compare id ., with Place, 462 U.S. at 698-700, 103 S.Ct. 2637. Instead, the Court reasoned that reasonable suspicion wasn’t necessary to justify the dog sniff because it could only detect contraband, and "any interest in possessing contraband cannot be deemed ‘legitimate,’ ... thus, governmental conduct that only reveals the possession of contraband ‘compromises no legitimate privacy interest.’ " Id. at 408, 125 S.Ct. 834 (quoting United States v. Jacobsen, 466 U.S. 109, 123, 104 S.Ct. 1652, 80 L.Ed.2d 85 (1984)).^[2]

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          C. Colorado Law: Pre-Amendment 64

         [¶28] Our search and seizure jurisprudence took a different path. In decades past, our opinions demonstrated a willingness to interpret the state constitution to afford broader protections than its federal counterpart. Yet, in recent years, we have moved away from this interpretive independence.

         [¶29] Article II, section 7 of the Colorado Constitution states:

The people shall be secure in their persons, papers, homes and effects, from unreasonable searches and seizures; and no warrant to search any place or seize any person or things shall issue without describing the place to be searched, or the person or thing to be seized, as near as may be, nor without probable cause, supported by oath or affirmation reduced to writing.

         [¶30] In Charnes v. DiGiacomo, this court first charted its own course in interpreting article II, section 7 to afford broader protections than the Fourth Amendment. 200 Colo. 94, 612 P.2d 1117 (1980). Charnes concerned a taxpayer’s challenge to a subpoena issued to his bank by the Colorado Department of Revenue seeking the taxpayer’s financial records. Id. at 1119. Applying United States v. Miller, this court concluded that the Fourth Amendment did not shield the taxpayer’s financial records from government seizure because the taxpayer could not claim any expectation of privacy in the information he shared with his bank through financial transactions. Id. at 1120 (citing 425 U.S. 435, 96 S.Ct. 1619, 48 L.Ed.2d 71 (1976)). But, the analysis did not end there. We then looked to article II, section 7 and concluded that the analytical framework announced in Katz — whether the defendant had a subjective expectation of privacy in his bank records that society was prepared to recognize as reasonable— was also the framework to be applied under the Colorado Constitution. See id. at 1120-21. Noting that Miller "does not determine the scope of protection provided to individuals in Colorado by the constitution of this state," we concluded that, under the Colorado Constitution, bank depositors have a reasonable expectation of privacy in records concerning their financial transactions held at banks in Colorado. Id. Charnes was only the first in a series of cases holding that article II, section 7 provides greater privacy protections than the Fourth Amendment. See, e.g., People v. Sporleder, 666 P.2d 135, 143-44 (Colo. 1983) (rejecting the U.S. Supreme Court’s reasoning in Smith v. Maryland, 442 U.S. 735, 99 S.Ct. 2577, 61 L.Ed.2d 220 (1979), to hold that the installation and use of a pen register constitutes a search under state law); People v. Corr, 682 P.2d 20, 27-28 (Colo. 1984) (applying the reasoning of Sporleder to conclude that a warrant is required to obtain telephone toll records); People v. Oates, 698 P.2d 811, 815-16 (Colo. 1985) (rejecting the reasoning of Karo, 468 U.S. 705, 104 S.Ct. 3296, and holding that the installation and presence of a tracking device in purchased commercial goods constitutes a search under the Colorado Constitution).

         [¶31] In People v. Unruh, we considered the constitutional permissibility of a dog sniff of a locked safe. 713 P.2d 370, 378-79 (Colo. 1986), abrogated by People v. Esparza, 2012 CO 22, 272 P.3d 367. We concluded that, despite the less intrusive nature of a dog sniff, it was a search because the defendant had a reasonable expectation of privacy in the locked safe. Id. In coming to this conclusion, we distinguished Place, noting that the sniff of a person’s luggage at an airport was not deemed a search because the person has "no reasonable expectation of privacy from an investigative technique as non-intrusive as a dog sniff" at the airport. Id. at 378. We then had to decide whether a warrant was necessary to deploy the drug-detection dog, or whether "something less than probable cause" could justify the sniff. Id. We looked to Terry v. Ohio, 392 U.S. 1, 30-31, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968), where the U.S. Supreme Court held that an officer may conduct a stop if he has reasonable suspicion criminal activity is occurring. We analogized

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an exploratory dog sniff to the brief investigatory stops at issue in Terry, and we concluded that the proper "balance between governmental and individual interests in this case" necessitated that there be reasonable suspicion to justify the exploratory sniff. Unruh, 713 P.2d at 379. Our reasoning rested primarily on two principles: (1) the defendant had a reasonable expectation of privacy in the item searched (his locked safe), and (2) a dog sniff, though a search, was a less intrusive search than a traditional search by hand. Id. at 377-79.

         [¶32] In People v. Haley, we applied the reasoning of Unruh to conclude that a dog sniff resulting from an impermissibly prolonged traffic stop violated the protections of article II, section 7.^[3] 41 P.3d 666, 673-74, 676-77 (Colo. 2001), abrogated by Esparza, 2012 CO 22, 272 P.3d 367. This was so because the defendants had "a privacy interest in their persons and vehicle being free from unreasonable governmental intrusion, and the drug investigation following the traffic stop in this case required reasonable suspicion for the dog sniff search to proceed." Id. at 674. We acknowledged that "automobiles enjoy a lesser expectation of privacy in our society than private homes," but we also noted that "citizens have a reasonable expectation of privacy from search and seizure in their cars and in their persons as they travel the state’s roads." Id. at 672 (citing New York v. Class, 475 U.S. 106, 112, 106 S.Ct. 960, 89 L.Ed.2d 81 (1986) ("A citizen does not surrender all the protections of the Fourth Amendment by entering an automobile.")).

         [¶33] However, in People v. Esparza, we reviewed our prior precedent on dog sniffs and, in doing so, narrowed its scope. 2012 CO 22, 272 P.3d 367. We concluded that, "[d]espite our broad language purporting to address dog sniffs in general," our earlier decisions suggested a "more limited rule" was appropriate. Id. at ¶ 9, 272 P.3d at 369. Specifically, we noted that our dog-sniff jurisprudence has "been concerned with the nature of the particular container being pursued and any official conduct making it possible for a trained drug dog to sniff the container in the first place." Id. at ¶ 8, 272 P.3d at 369. Ultimately, we held "that an interest in possessing contraband cannot be deemed legitimate under the state constitution any more than under the federal constitution, and that official conduct failing to compromise any legitimate interest in privacy cannot be deemed a search under the state constitution any more than under the federal constitution." Id. at ¶ 2, 272 P.3d at 368. Like the U.S. Supreme Court, we based our holding in part on the purportedly binary nature of the dog’s sniff. The sniff, we reasoned, could only communicate either the presence or absence of contraband. Id. at ¶ 11, 272 P.3d at 370.

         [¶34] Esparza thus represented a kind of return to the federal fold. The state of the law was thus: (1) under the automobile exception, an officer may search a car without a warrant if that officer has probable cause to believe there is contraband in the car; (2) an officer doesn’t need reasonable suspicion to walk a drug-detection dog around a lawfully stopped vehicle because the alert indicates only the presence of contraband, and people do not have a legitimate expectation of privacy in contraband; and (3) an alert from a drug-detection dog could provide probable cause for a subsequent hand search of the car. See id. at ¶¶ 10-12, 272 P.3d at 370; see also People v. Mason, 2013 CO 32, ¶ 10, 310 P.3d 1003, 1005 ("It is now settled that walking a trained narcotics detection dog around a car that has not been unlawfully stopped or detained does not implicate the protections of either the Fourth Amendment or Article II, section 7 of the state constitution."). And so it has been for the better part of a decade.

          D. Colorado Law: Post-Amendment 64

         [¶35] Has the passage of Amendment 64 altered this settled terrain? We began to explore this question in our recent decisions in People v. Zuniga, 2016 CO 52, 372 P.3d 1052, and People v. Cox, 2017 CO 8, 401 P.3d 509. In both Zuniga and Cox, we found probable cause supporting an automobile search based on a confluence of factors, including the positive alert of a drug-detection dog that was trained to alert to marijuana. Yet, in Zuniga, we concluded that the alert was

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legally ambiguous because a drug-detection dog can’t distinguish legal marijuana from illegal marijuana, or legal marijuana from illegal narcotics. See ¶¶ 18-23, 372 P.3d at 1057-59. Despite this ambiguity, we held that the alert was still relevant to the overall probable cause analysis. Id. Likewise in Cox, we concluded that the positive alert of a drug-detection dog was one factor, among many, supporting a finding of probable cause to search a stopped vehicle.¶ 17, 401 P.3d at 512-13.

         [¶36] In both Zuniga and Cox, we declined to address (1) whether the sniff of a dog trained to detect marijuana was a search, and (2) whether a positive alert from a dog trained to detect marijuana alone could establish probable cause. Significantly however, these two recent decisions suggest the answer to the latter question is no. We acknowledged that, with the legalization of small amounts of marijuana, a dog’s alert doesn’t provide a yes-or-no answer to the question of whether illegal narcotics are present in a vehicle. At most, the alert could be "suggestive of criminality," but not determinative on its own. See Zuniga, ¶ 23, 372 P.3d at 1059. Had the alert alone sufficed, there would have been no need to evaluate other circumstances in either Zuniga or Cox . Yet, we did just that. Thus, in finding that an alert from a drug-detection dog trained to find marijuana is ambiguous, Zuniga and Cox represent a tentative step away from the federal approach. See, e.g., Harris, 568 U.S. at 240, 247-48, 133 S.Ct. 1050 (concluding that an alert from a well-trained, reliable drug-detection dog could supply probable cause to search a vehicle).

         [¶37] To be sure, marijuana remains illegal under federal law. The Federal Controlled Substances Act prohibits the possession of marijuana for nearly all uses. 21 U.S.C. § 812(c)(10) (2012); 21 U.S.C. § 812(b)(1)(A)-(C) (2012); 21 U.S.C. § 844(a) (2012). "There is no exception for marijuana use for medical purposes, nor is there an exception for use in compliance with state law." People v. Crouse, 2017 CO 5, ¶ 11, 388 P.3d 39, 42 (citing Gonzales v. Raich, 545 U.S. 1, 14, 125 S.Ct. 2195, 162 L.Ed.2d 1 (2005)). Consequently, marijuana remains contraband under federal law and, arguably, Kilo’s sniff was not a search under the U.S. Supreme Court’s interpretation of the Fourth Amendment in Caballes .^[4] See McKnight, ¶ 18 n.4. This, however, leaves unanswered the question of whether Kilo’s sniff was nonetheless a search under the corresponding provisions of our state constitution.^[5]

         [¶38] We have opined that, despite the substantial similarity between article II, section 7 and the Fourth Amendment, "we are not bound by the United States Supreme Court’s interpretation of the Fourth Amendment when determining the scope of state constitutional protections." Sporleder, 666 P.2d at 140. "There is no reason to think, as an interpretive matter, that constitutional guarantees of independent sovereigns, even guarantees with the same or similar words, must be construed in the same ...