Aligning Colorado’s Drug Dog Jurisprudence with the U.S. Supreme Court’s: People v. Esparza

Michael Matthews[1]

In People v. Esparza, decided March 26, 2012, the Colorado Supreme Court held that a drug sniffing dog can smell outside a defendant’s parked vehicle without the police having reasonable suspicion of the presence of contraband, and that such use of the dog does not constitute a “search” under the Colorado Constitution’s protections against unreasonable search and seizure.[2] In so holding, the Court abrogated a number of its prior decisions[3] and significantly changed Colorado law, perhaps without sufficiently addressing stare decisis concerns.

Twice in 2011, in separate but nearly identical incidents, Heather Esparza (“Defendant”) was arrested for driving with a suspended license. In both instances, after her arrest, “by request and in conformity with department policy,” Defendant’s pickup truck was left at the place of arrest. A drug sniffing dog subsequently smelled the exterior of the truck and alerted to the presence of contraband. After police entered the vehicle and found a pipe and methamphetamine, Defendant was charged, in both instances, with possession of drug paraphernalia and a schedule II controlled substance.[4]

At trial, the district court suppressed the contraband evidence because it found that, in both incidents, the police lacked the reasonable suspicion required under the Colorado Constitution and prior case law for “bringing a trained narcotics detection dog within detection range.”[5] The district court relied mainly on People v. Haley, where employing a drug dog outside a car in similar circumstances without reasonable suspicion was held an unconstitutional search under the Colorado Constitution.[6] Upon interlocutory appeal by the state, the issue of drug sniffs, reasonable suspicion, and what constitutes a constitutionally protected search came before the Colorado Supreme Court once again.

The majority opinion, authored by Justice Nathan B. Coats—part of the three-justice dissent in Haley—began by looking to the U.S. Supreme Court’s 2005 decision in Illinois v. Cabelles, where walking a trained drug dog around a lawfully stopped and lawfully detained vehicle was held not to invoke Fourth Amendment protections from unreasonable search and seizure.[7] That holding rests on the idea that privacy rights are limited to those interests that are legitimate: an interest in possessing contraband cannot be deemed legitimate, and accordingly, any police conduct revealing only the presence or absence of contraband does not reach the level of a constitutionally-protected search.[8]  

From here, the majority cited Colorado Supreme Court precedent where state constitutional protections against unreasonable searches required reasonable suspicion for a drug sniff[9] before laying out the premise used to decide Esparza: “[i]n neither Unruh nor any of the handful of other dog-sniff cases decided by this court, however, has that proposition actually controlled the outcome of a case.”[10] Using this idea—that the dispositive factors in the court’s previous drug sniff cases were either the presence of reasonable suspicion, the nature of what was searched, or the lawfulness of the stop or detention of the vehicle rather than whether the drug sniff itself was supported by reasonable suspicion—the majority goes on to distinguish the two most seemingly on-point cases. In Reyes, there was reasonable suspicion so the court had no occasion to explicitly state whether the drug sniff itself required it.[11] And in Haley, the case relied on by the district court, the drug sniff only was unconstitutional in combination with an unlawfully prolonged detention of the car involved.[12]

Thus, the drug sniff was constitutional, because: (1) Defendant’s vehicle was not illegally stopped or detained in both instances of arrest; (2) the Defendant had no legitimate privacy interest in contraband; and (3) a drug sniffing dog can indicate nothing more than either the presence or absence of contraband, the lack of reasonable suspicion was irrelevant in Esparza.[13] In highlighting these considerations, the majority carefully distinguished the Colorado Supreme Court’s prior cases and fashioned a new rule more in line with the U.S. Supreme Court’s interpretation of unreasonable search and seizure protections as they relate to drug sniffs. After Esparza, a drug dog’s sniff of the outside of a vehicle or container, in and of itself, does not infringe on legitimate privacy interests in the contents of that vehicle or container, and accordingly does not constitute a search under the Colorado—or federal—Constitution that would require at least reasonable suspicion on the part of law enforcement or government personnel.[14]

The majority opinion in Esparza raised a number of potentially troubling issues, most of which were alluded to in the dissent penned by Justice Gregory J. Hobbs, Jr.—who wrote the majority opinion in Haley that the district court erroneously relied on. For one, both the U.S. and Colorado Supreme Courts have relied heavily on the premise that drug dogs only alert to the presence or absence of contraband; in other words, the use of the dog cannot itself be considered a “search” because it only leads to an invasion of privacy where there is no legitimate privacy interest—e.g. when there is contraband, which supposedly is the only time that the dog will alert. Justice Hobbs correctly asserted that “[i]t has always been a fallacy to suggest that finding such items justifies a search” in the first place, before going on further to highlight the very real possibility of false positives yielded by drug sniffing dogs.[15] And even aside from the tautological reasoning and questions of reliability, under state law, the widespread use of medical marijuana may further undermine the Colorado Supreme Court’s assumption that a drug sniffing dog will only alert to the presence or absence of illegal contraband, as a dog would presumably and correctly alert to medical marijuana that may not be contraband at all.

Furthermore, the majority’s attempt to distinguish Haley fell short.[16] The majority separated the unlawfully prolonged detention of the vehicle from the dog sniff itself in Haley.[17] However, as Justice Hobbs points out, without reasonable suspicion, the sniff itself was what turned the Haley detention unlawful.[18] In other words, the majority’s assertion that the holding in Haley was not based on an absence of reasonable suspicion for a drug sniff alone is misleading. From this interpretation requiring an unlawful stop or prolonged detention for unconstitutionality, the majority points to there being “no suggestion” on appeal of an unlawfully prolonged detention to distinguish Haley and hold against Defendant.[19] Of course, this is patently unfair to Defendant who realistically had no reason to “suggest” the detention was unlawful based on the ostensibly straightforward precedent set out in Haley—that a drug sniff in this context required reasonable suspicion. Overall then, with regard to the crucial distinguishing of Haley, the majority focuses heavily on aligning the law in Colorado with the U.S. Supreme Court’s approach to drug dogs and unreasonable searches, but in its haste appears to have foregone a required stare decisis analysis to abrogate a clearly applicable holding.[20]

So what really has happened here? It may be that two of the Haley dissenters—Justices Coats and Rice[21]—found the three newer Justices—Justices Boatright, Marquez, and Eid—more willing to side with them, especially in light of the U.S. Supreme Court’s post-Haley, 2005 holding in Caballes.[22] This left only two Justices—Justices Hobbs and Bender—from the Haley majority to oppose this shift.[23] This alone is not problematic, but in combination with a possible failure to conduct a sufficient stare decisis analysis, it becomes cause for concern. As the dissent pointed out, this somewhat unexplained focus on alignment with the U.S. Supreme Court and the federal Constitution may unreasonably subject Coloradoans to drug sniffs without any reasonable suspicion.[24] Overall then, the Colorado Supreme Court seems to have significantly changed course without any substantial explanation, an especially troublesome development for Heather Esparza and other defendants that might find themselves similarly situated in the future.


[1] J.D. Candidate, 2013, University of Denver Sturm College of Law

[2] People v. Esparza, 272 P.3d 367, ¶¶ 13-14 (Colo. 2012) (5-2 decision) (citing Colo. Const. art. II, § 7 (“The people shall be secure in their persons, papers, homes and effects, from unreasonable searches and seizures. . . .”)).

[3] People v. Unruh, 713 P.2d 370 (Colo. 1986); People v. Wieser, 796 P.2d 982 (Colo. 1990); People v. Boylan, 854 P.2d 807 (Colo. 1993); People v. May, 886 P.2d 280 (Colo. 1994); People v. Reyes, 956 P.2d 1254 (Colo. 1998); People v. Haley, 41 P.3d 666 (Colo. 2001).

[4] Esparza, 272 P.3d ¶¶ 3-4.  

[5] Id. ¶ 1.

[6] 41 P.3d 666, 669 (Colo. 2001) (4-3 decision).

[7] Esparza, 272 P.3d ¶ 6 (citing Illinois v. Caballes, 543 U.S. 405, 409 (2005)).

[8] Id.

[9] Id. ¶ 7 (citing People v. Unruh, 713 P.2d 370, 379 (Colo. 1986)).

[10] Id.  

[11] People v. Reyes, 956 P.2d 1254, 1255 (Colo. 1998).

[12] People v. Haley, 41 P.3d 666, 676 (Colo. 2001) (“[W]e conclude that the police in this case lacked reasonable suspicion of drug trafficking and incorrectly employed Haley's denial of permission to search the car as reasonable suspicion to prolong the traffic stop in order to conduct a drug investigation.”) (emphasis added).

[13] See Esparza, 272 P.3d ¶ 10.

[14] Id. ¶ 14.

[15] Id. ¶ 5 (Hobbs, J., dissenting) (citing Dan Hinkel & Joe Mahr, Tribune Analysis: Drug-sniffing Dogs in Traffic Stops Often Wrong, Chicago Tribune, Jan. 6, 2011,

[16] Id. ¶ 3 (“There is no meaningful distinction between the facts of these two cases.”).

[17] See supra note 12 and accompanying text.

[18] Esparza, 272 P.3d at ¶ 3 (Hobbs, J., dissenting).

[19] Id. ¶ 10 (majority decision).

[20] Id. ¶ 4 (Hobbs, J., dissenting).                                                                   

[21] People v. Haley, 41 P.3d 666, 677 (Colo. 2001) (dissenting opinion).

[22] Illinois v. Caballes, 543 U.S. 405 (2005).

[23] Haley, 41 P.3d 666 (majority opinion).

[24] Esparza, 272 P.3d ¶ 7 (Hobbs, J., dissenting).