United States of America v. Juventino L. Plancarte

In the
United States Court of Appeals
For the Seventh Circuit
____________________
No. 23-2224
U NITED S TATES OF A MERICA,
Plaintiff-Appellee,
v.
JUVENTINO L. PLANCARTE,
Defendant-Appellant.
____________________
Appeal from the United States District Court for the
Western District of Wisconsin.
No. 22-cr-00064 — William M. Conley, Judge.
____________________
A RGUED M AY 20, 2024 — DECIDED J UNE 28, 2024
____________________
Before F LAUM , BRENNAN , and K OLAR , Circuit Judges.
F LAUM , Circuit Judge. During a traffic stop, Wisconsin po-
lice officers used a K-9 unit to sniff a car they suspected was
involved in drug trafficking. The dog returned a positive
alert, so the officers searched the car and found almost eleven
pounds of methamphetamine in its trunk. On appeal, defend-
ant Juventino Plancarte, who was inside the car during the
stop, challenges the district court’s denial of his motion to
suppress. We affirm.

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2 No. 23-2224
I. Background
A. Factual Background
On the evening of January 20, 2022, Officer James Man-
cuso was conducting surveillance in La Crosse, Wisconsin,
when a state trooper notified him of a vehicle of interest head-
ing in his direction. Soon after, Mancuso saw a car matching
the trooper’s description and tailed it for several hours. As he
followed the car, he observed the vehicle exhibiting behavior
consistent with drug trafficking activity.
Mancuso also noticed that the car had unlawful window
tints, so he directed two other officers to perform a traffic stop.
During the stop, Officer Aaron Westpfahl and his K-9 partner
Loki arrived on the scene. Loki conducted a sniff and alerted
to drugs in the car. The officers then searched the car and dis-
covered a backpack containing “a large amount of a crystal-
like substance” in its trunk. They arrested the car’s occupants,
including Plancarte. Lab testing later revealed that the sub-
stance in the backpack was 10.96 pounds of methampheta-
mine.
B. Procedural Background
A grand jury indicted Plancarte on two counts related to
methamphetamine distribution. He moved to suppress the
evidence obtained after Loki’s sniff. According to Plancarte,
Loki can identify both illegal marijuana products and legal
products that come from cannabis plants. Since Loki could
theoretically alert officers to legal cannabis products,
Plancarte argues that the sniff violated the Fourth Amend-
ment because it was a warrantless search unsupported by
probable cause.

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No. 23-2224 3
A magistrate judge held an evidentiary hearing before rul-
ing on Plancarte’s motion. At the hearing, Westpfahl testified
that Loki was trained to identify several illegal drugs, includ-
ing marijuana and methamphetamine, based on their scent. If
Loki smelled one of those drugs during a sniff, he would ex-
hibit a behavioral signal indicating a “positive alert.” West-
pfahl also explained that Loki’s positive alerts have never un-
covered physical evidence of legal cannabis products. Even
so, an expert witness testified that dogs cannot tell the differ-
ence between illegal marijuana and legal cannabis products
based on smell.
Westpfahl also presented data to illustrate Loki’s accuracy
during sniffs. The data showed that, when officers searched a
vehicle after Loki returned a positive alert, they discovered
contraband about 80% of the time. If the ensuing search did
not reveal contraband, Westpfahl would later ask the vehi-
cle’s owner or occupants if any contraband had recently been
in the car. In response to that inquiry, over half of respondents
confirmed that contraband had recently been in the sniffed
vehicle. On one occasion, after Loki returned what appeared
to be a false positive during a car sniff, the vehicle’s owner
told Westpfahl that he frequently smoked legal cannabis
products in the car. There is no evidence, however, corrobo-
rating that the cannabis product in that inquiry was legal.
Following the evidentiary hearing, the magistrate judge
issued a report and recommendation denying Plancarte’s
suppression motion. The district court adopted those recom-
mendations, and Plancarte later pleaded guilty to both drug
charges. Plancarte received concurrent 180-month sentences,

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4 No. 23-2224
and he now appeals the district court’s denial of his motion to
suppress.1
II. Discussion
“In considering a district court’s denial of a motion to sup-
press, we review questions of law de novo and findings of fact
for clear error.” United States v. Beechler, 68 F.4th 358, 364 (7th
Cir. 2023).
“The Fourth Amendment protects ‘[t]he right of the peo-
ple to be secure in their persons, houses, papers, and effects,
against unreasonable searches and seizures.’” Utah v. Strieff,
579 U.S. 232, 237 (2016) (alteration in original) (quoting U.S.
Const. Amend. IV). As its plain text indicates, “the Fourth
Amendment is triggered only by a search or seizure.” Hess v.
Garcia, 72 F.4th 753, 764 (7th Cir. 2023).
“Two lines of precedent govern whether officer conduct
amounts to a search.” United States v. Lewis, 38 F.4th 527, 533
(7th Cir. 2022), cert. denied, 143 S. Ct. 2499 (2023). The first is
called the “property-based approach,” which applies when
“an officer enters a constitutionally protected area, such as the
home, for the purpose of gathering evidence against the prop-
erty owner.” Id. The second is called the “privacy-based ap-
proach.” Id. at 534. Under that approach, we consider whether
government action invaded a person’s actual, subjective ex-
pectation of privacy that society recognizes as reasonable. Id.
at 535 (7th Cir. 2022) (discussing Katz v. United States, 389 U.S.
347, 361 (1967) (Harlan, J., concurring)); see also United States
1 Plancarte, in his opening brief, argued that he is eligible for safety
valve relief. His reply brief concedes that Pulsifer v. United States, 601 U.S.
124, 127–28 (2024), forecloses that argument.

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No. 23-2224 5
v. Wood, 16 F.4th 529, 534 (7th Cir. 2021) (explaining that “the
ultimate touchstone of the Fourth Amendment is reasonable-
ness” when determining what constitutes a search (citation
and internal quotation marks omitted)).
Plancarte does not suggest—and rightly so—that the area
around a car on a public road is a “constitutionally protected
area.” Lewis, 38 F.4th at 533. As a result, we instead focus on
the privacy-based approach.
However, “canine inspection of an automobile during a
lawful traffic stop[] do[es] not violate the ‘reasonable expec-
tation of privacy’ described in Katz.” Florida v. Jardines, 569
U.S. 1, 10 (2013) (discussing Illinois v. Caballes, 543 U.S. 405,
409–10 (2005)). Rather, when “performed on the exterior of [a]
car” during a “lawful[] seiz[ure] for a traffic violation,” dog
sniffs “generally do[] not implicate legitimate privacy inter-
ests.” Caballes, 543 U.S. at 409. “A ‘canine sniff’ by a well-
trained [drug] detection dog,” therefore, “d[oes] not consti-
tute a ‘search’ within the meaning of the Fourth Amend-
ment.” United States v. Place, 462 U.S. 696, 707 (1983); see also
Caballes, 543 U.S. at 410.
Two related principles underscore this conclusion. First,
dog sniffs on the exterior of an automobile during a traffic
stop are “not designed to disclose any information other than
the presence or absence of narcotics.” City of Indianapolis v. Ed-
mond, 531 U.S. 32, 40 (2000). Second, they are “generally
likely … to reveal only the presence of contraband.” Caballes,
543 U.S. at 409. Together, these concepts illustrate that “the
manner in which information is obtained” during a sniff is
“much less intrusive than a typical search” and results in only
a “limited disclosure,” which protects against the property

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6 No. 23-2224
owner’s “embarrassment and inconvenience.” Place, 462 U.S.
at 707.
Despite this precedent, which affirms the constitutionality
of K-9 sniffs in public places, Plancarte nevertheless argues
that the legalization of some cannabis products changed the
Fourth Amendment landscape for dog sniffs. He contends
that K-9s like Loki cannot distinguish between illegal mariju-
ana and other, legal cannabis products, so drug sniffs reveal
more than just contraband. According to Plancarte, that un-
dercuts the holdings of Place and Caballes, which emphasized
that dog sniffs are unique—and not searches—because they
alert only to illegal items. Caballes, 543 U.S. at 409; Place, 462
U.S. at 707.
He instead points to Kyllo v. United States, a case in which
the Supreme Court limited the warrantless use of thermal im-
aging technology to observe activity inside a home. 533 U.S.
27, 40–41 (2001). There, the Court explained that “the Govern-
ment[’s] use[] [of] a device that is not in general public use[]
to explore details of the home that would previously have
been unknowable without physical intrusion … is a ‘search’
and is presumptively unreasonable without a warrant.” Id. at
40. Plancarte urges us to apply Kyllo here because drug detec-
tion dogs, like thermal imaging technology, are “super-sensi-
tive instrument[s],” unavailable to the general public and ca-
pable of revealing “details … that would … be[] unknowable
without physical intrusion.” United States v. Whitaker, 820 F.3d
849, 853 & n.1 (7th Cir. 2016).
But there is a problem with extending Kyllo to these facts:
Loki’s sniff occurred outside the home. It is well established
that the home is “[a]t the very core of the Fourth Amend-
ment,” Kyllo, 533 U.S. at 31 (citations and internal quotation

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No. 23-2224 7
marks omitted), and “first among equals,” Jardines, 569 U.S. at
6. “The expectation of privacy with respect to one’s automo-
bile” or in a public space is therefore “significantly less than
that relating to one’s home.” United States v. Lozano, 171 F.3d
1129, 1131 (7th Cir. 1999) (quoting United States v. Velarde, 903
F.2d 1163, 1166 (7th Cir. 1990)).
Our dog sniff jurisprudence itself sets apart dog sniffs oc-
curring in public areas from those that involve homes or other
private places. Whitaker, 820 F.3d at 853 (distinguishing
Fourth Amendment concerns attendant to using drug-sniff-
ing dogs on homes compared to sniffs performed in public
places). So, while using “trained police dogs to investigate the
home … is a ‘search’ within the meaning of the Fourth
Amendment,” Jardines, 569 U.S. at 11–12, dog sniffs con-
ducted in public places are generally not, Caballes, 543 U.S. at
409. Just as is the case here, the sniffs in both Place and Caballes
occurred in public areas, and “[n]either implicated the Fourth
Amendment’s core concern of protecting the privacy of the
home.” Whitaker, 820 F.3d at 853. Since Kyllo’s holding also
cannot be divorced from that context, we decline to extend it
to these facts. See 533 U.S. at 40 (explaining that “the Fourth
Amendment draws a firm line at the entrance to the house”
(citation and internal quotation marks omitted)).
Another problem remains for Plancarte: Courts have long
acknowledged and tolerated the imperfection of drug detec-
tion dogs. For example, in United States v. Bentley, we con-
cluded that a dog sniff supported probable cause despite the
dog’s 59.5% accuracy rate. 795 F.3d 630, 636–37 (7th Cir. 2015);
see also Caballes, 543 U.S. at 409 (recognizing that, even “if
properly conducted,” dog sniffs are merely “generally likely[]
to reveal only the presence of contraband”); United States v.

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8 No. 23-2224
Perez, 29 F.4th 975, 986–87 (8th Cir. 2022) (discussing instances
in which drug-sniffing dogs had been deemed reliable despite
accuracy rates under 60%); United States v. Kennedy, 131 F.3d
1371, 1378 (10th Cir. 1997) (stating that a search following a
positive alert by a dog with at least a 71% accuracy rate satis-
fied probable cause); Whitaker, 820 F.3d at 853 n.1 (explaining
that “the results and accuracy of dog searches are subject to
detailed research and analysis”). But see Caballes, 543 U.S. at
410 (Souter, J., dissenting) (describing dog sniff jurisprudence
as resting on the “untenable … assumption that trained sniff-
ing dogs do not err”). While Bentley occurred in the probable
cause context, that error rate is much higher than what can be
attributed to Loki. And as for Loki, “a very low percentage of
false positives is not necessarily fatal to a finding that a drug
detection dog is properly trained and certified.” United States
v. Diaz, 25 F.3d 392, 396 (6th Cir. 1994).
Even if drug sniffing dogs struggle to differentiate be-
tween illegal marijuana and other legal cannabis products,
Loki does not. On the contrary, at the time of the suppression
hearing, Loki had returned 215 positive alerts from a total of
328 sniffs during his career. Of those 215 positive alerts, Loki’s
sniffs led to the discovery of physical evidence of contraband
around 80% of the time. Furthermore, in more than half of
“false positive” cases, officers later learned that drugs had re-
cently been inside the vehicle, further decreasing Loki’s “false
positive” rate.
At most, Loki may have—on a single occasion—returned
a false positive where the car’s operator later admitted that he
routinely smoked legal cannabis products in the vehicle. Even
looking beyond the fact that officers did not recover cannabis
products of any kind from that operator’s vehicle and were

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No. 23-2224 9
otherwise unable to confirm whether the cannabis product in
question was, in fact, legal, that lone instance does not mean
Loki is not “well-trained.” This rings especially true because
physical evidence of legal cannabis products has never been
discovered after any of Loki’s positive alerts. Instead, that sin-
gle instance resembles a false positive alert, and we have
never held that a low rate of false positive alerts converts an
otherwise permissible dog sniff into a search.
Loki, a reliable drug detection dog, conducted an open-air
sniff on a public road during an ordinary traffic stop. Place
and Caballes confirm that a sniff performed in this manner is
not a Fourth Amendment search because it does not disrupt
any reasonable expectation of privacy. For that reason, the
district court appropriately denied Plancarte’s motion to sup-
press.
III. Conclusion
For the foregoing reasons, we A FFIRM the district court’s
denial of Plancarte’s motion to suppress.

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