              This opinion is subject to revision before final
                   publication in the Pacific Reporter.

                                2015 UT 2

                                 IN THE
      SUPREME COURT OF THE STATE OF UTAH
                            ———————
                            STATE OF UTAH,
                              Respondent,
                                    v.
                  EDWARD JOSEPH STRIEFF, JR.,
                             Petitioner.
                         ———————
                           No. 20120854
                      Filed January 16, 2015
                         ———————
             On Certiorari to the Utah Court of Appeals
                         ———————
                    Third District, Salt Lake
             The Honorable Michele M. Christiansen
                          No. 071900011
                         ———————
                             Attorneys:
    Sean D. Reyes, Att’y Gen., Jeffrey S. Gray, Asst. Att’y Gen.,
                  Salt Lake City, for respondent
   Joan C. Watt, Robert K. Engar, Salt Lake City, for petitioner
                        ———————
     JUSTICE LEE authored the opinion of the Court, in which
   CHIEF JUSTICE DURRANT, ASSOCIATE CHIEF JUSTICE NEHRING,
          JUSTICE DURHAM, and JUSTICE PARRISH joined.
                        ———————

 JUSTICE LEE, opinion of the Court:
  ¶1 In this case we are asked to determine the applicability of
the “attenuation” exception to the exclusionary rule to a fact pat-
tern addressed in a broad range of lower-court opinions but not
by the United States Supreme Court. The essential fact pattern in-
volves an unlawful detention leading to the discovery of an arrest
warrant followed by a search incident to arrest. The attenuation
inquiry is essentially a proximate cause analysis. It asks whether
the fruit of the search is tainted by the initial, unlawful detention,
or whether the taint is dissipated by an intervening circumstance.
As applied to the outstanding warrant scenario, the question pre-
                             STATE v. STRIEFF
                          Opinion of the Court

sented is whether and how to apply the attenuation doctrine in
this circumstance.
  ¶2 The lower courts are in disarray in their application of the
attenuation doctrine to the outstanding warrant scenario. In some
courts the discovery of an outstanding warrant is deemed a
“compelling” or dispositive “intervening circumstance,” purging
the taint of an initially unlawful detention upon a showing that
the detention was not a “purposeful” or “flagrant” violation of the
Fourth Amendment. 1 In other courts, by contrast, the outstanding
warrant is a matter of “‘minimal importance,’” and the doctrine’s
applicability is strictly curtailed. 2
  ¶3 We adopt a third approach. We conclude that the attenua-
tion exception is limited to the general fact pattern that gave rise
to its adoption in the United States Supreme Court—of a volun-
tary act of a defendant’s free will (as in a confession or consent to
search). For cases arising in the context of two parallel acts of po-
lice work—one unlawful and the other lawful—we interpret the
Supreme Court’s precedents to dictate the applicability of a differ-
ent exception (inevitable discovery).
  ¶4 Our holding is rooted in our attempt to credit the terms of
the attenuation doctrine as prescribed in the Supreme Court’s
opinions, while also respecting the parallel doctrine of inevitable
discovery. Thus, we read the Court’s attenuation cases to define
the conditions for severing the proximate causal connection be-
tween a threshold act of police illegality and a subsequent, inter-
vening act of a defendant’s free will. And in the distinct setting of
both unlawful and then lawful police activity, we deem the inevi-
table discovery doctrine to control. Because this case involves no
independent act of a defendant’s free will and only two parallel
lines of police work, we hold that the attenuation doctrine is not
implicated, and thus reverse the lower court’s invocation of that
doctrine in this case.




 1   United States v. Green, 111 F.3d 515, 522, 23 (7th Cir. 1997).
 2  State v. Moralez, 300 P.3d 1090, 1102 (Kan. 2013) (quoting State
v. Hummons, 253 P.3d 275, 278 (Ariz. 2011)).

                                    2
                         Cite as: 2015 UT 2
                       Opinion of the Court

                            I. Background
  ¶5 In December, 2006, an anonymous caller left a message on
a police drug tip line reporting “narcotics activity” at a South Salt
Lake City residence. Police officer Douglas Fackrell subsequently
conducted intermittent surveillance of the residence for approxi-
mately three hours over the course of about one week. During
that time, the officer observed “short term traffic” at the home.
The traffic was not “terribly frequent,” but was frequent enough
that it raised Officer Fackrell’s suspicion. In Officer Fackrell’s
view, the traffic was more than one would observe at a typical
house, with visitors often arriving and then leaving within a cou-
ple of minutes. Thus, the officer concluded that traffic at the resi-
dence was consistent with drug sales activity.
  ¶6 During his surveillance of the residence, Officer Fackrell
saw Edward Strieff leave the house—though he did not see him
enter—and walk down the street toward a convenience store. As
Strieff approached the convenience store, Officer Fackrell ordered
Strieff to stop in the parking lot. Strieff complied. Officer Fackrell
testified that he detained Strieff because “[Strieff] was coming out
of the house that [he] had been watching and [he] decided that
[he’d] like to ask somebody if [he] could find out what was going
on [in] the house.” Officer Fackrell identified himself as a police
officer, explained to Strieff that he had been watching the house
because he believed there was drug activity there, and asked
Strieff what he was doing there.
  ¶7 Officer Fackrell also requested Strieff’s identification,
which Strieff provided. Officer Fackrell then called dispatch and
asked them to run Strieff’s ID and check for outstanding warrants.
Dispatch responded that Strieff had “a small traffic warrant.” Of-
ficer Fackrell then arrested Strieff on the outstanding warrant and
searched him incident to the arrest. During the search, the officer
found a baggie of methamphetamine and drug paraphernalia in
Strieff’s pockets.
  ¶8 Strieff was charged with unlawful possession of metham-
phetamine and unlawful possession of drug paraphernalia. He
moved to suppress the evidence seized in the search incident to
his arrest, arguing that it was fruit of an unlawful investigatory
stop. The State conceded that Officer Fackrell had stopped Strieff
without reasonable articulable suspicion (given that Officer
Fackrell had not seen Strieff enter the house, did not know how
long he had been there, and knew nothing of him other than that


                                  3
                           STATE v. STRIEFF
                        Opinion of the Court

he left the house). The State argued, however, that the exclusion-
ary rule did not bar the evidence seized in the search because the
attenuation exception to the exclusionary rule applied.
  ¶9 The district court agreed and denied Strieff’s motion to
suppress and subsequent motion to reconsider. First, the district
court found that Officer Fackrell “believed he had seen enough
short-term traffic at the house to create a reasonable suspicion that
the house was involved in drug activity,” and thus that the pur-
pose of the stop “was to investigate a suspected drug house.” Se-
cond, while acknowledging that Officer Fackrell’s belief that he
had sufficient suspicion to stop Strieff was incorrect, the court
concluded that “the stop was not a flagrant violation of the Fourth
Amendment” but a “good faith mistake on the part of the officer
as to the quantum of evidence needed to justify an investigatory
detention.” Finally, “[w]eighing the factors in their totality,” the
court found “suppression to be an inappropriate remedy,” con-
cluding that “the search was conducted after discovering an out-
standing warrant and arresting the Defendant on that warrant, an
intervening circumstance that Officer Fackrell did not cause and
could not have anticipated.”
  ¶10 Strieff entered a conditional guilty plea to charges of at-
tempted possession of a controlled substance and possession of
drug paraphernalia, reserving his right to appeal the order deny-
ing his motions to suppress and reconsider. The court of appeals
affirmed under the attenuation exception to the exclusionary rule
recognized in Brown v. Illinois, 422 U.S. 590 (1975). State v. Strieff,
2012 UT App 245, 286 P.3d 317. Applying the factors set forth in
Brown, a majority of the court of appeals concluded that the dis-
covery of an outstanding arrest warrant was a powerful “inter-
vening circumstance” dissipating the taint of the unlawful deten-
tion, and that Officer Fackrell’s detention of Strieff was not a
“purposeful” or “flagrant” violation of the Fourth Amendment.
Id. at ¶¶ 21, 27. And although the “temporal proximity” of the
discovery of the warrant weighed against attenuation, the majori-
ty deemed that factor outweighed by the existence of an interven-
ing circumstance and the lack of a purposeful or flagrant viola-
tion. Id. at 29–30, 37.
 ¶11 Judge Thorne dissented. He disagreed with the majority’s
analysis of the attenuation factors as applied to this case. Id. at
¶¶46, 48–50. And he expressed discomfort with what he saw as an

                                  4
                         Cite as: 2015 UT 2
                       Opinion of the Court

inconsistency between the outcome of this case and that of State v.
Topanotes, 2003 UT 30, 76 P.3d 1159, a case arising under similar
facts but decided under the inevitable discovery exception. Strieff
filed a petition for certiorari, which we granted.
  ¶12 On certiorari, we review not the underlying decision of the
district court but the ultimate decision of the court of appeals—a
decision that merits no deference in our analysis. See State v. Verde,
2012 UT 60, ¶ 13, 296 P.3d 673. “That said, [t]he correctness of the
court of appeals’ decision turns, in part, on whether it accurately
reviewed the district court’s decision under the appropriate
standard of review.” Id. (alteration in original) (internal quotation
marks omitted). And the deference, if any, we owe to the district
court’s decision varies depending on the nature of the determina-
tion in question.
  ¶13 First, any factual determinations made by the district court
are entitled to substantial deference under a standard of review
for clear error. See Manzanares v. Byington (In re Adoption of Baby
B.), 2012 UT 35, ¶ 40, 308 P.3d 382. Second, to the extent the dis-
trict court’s decision implicated pure legal questions regarding the
terms and conditions of the attenuation exception, the court’s res-
olution of those questions is reviewed for correctness. See Hi-
Country Prop. Rights Grp. v. Emmer, 2013 UT 33, ¶¶ 13–14, 304 P.3d
851 (noting that threshold legal determinations embedded within
mixed determinations are reviewed for correctness like any other
determination of law). Finally, the district court’s application of
the attenuation exception to the facts of this case is likewise a de-
termination that is reviewed for correctness. See State v. Worwood,
2007 UT 47, ¶¶ 11–12, 164 P.3d 397. Although that decision is a
“mixed” determination of fact and law, it is one of those decisions
that is “law-like” in that our resolution of it lends itself to “con-
sistent resolution by a uniform body of appellate precedent.” In re
Baby B., 2012 UT 35, ¶ 44.
     II. The Exclusionary Rule and the Attenuation Doctrine
  ¶14 Although this case concerns a single exception to the exclu-
sionary rule (attenuation), that exception is best conceptualized
within the broader context of the rule and as one of a range of ex-
ceptions that define its limits. We accordingly start with first prin-
ciples, explaining the basis for the rule and describing the con-
tours of various exceptions that are related to the attenuation doc-


                                  5
                           STATE v. STRIEFF
                        Opinion of the Court

trine (independent source and inevitable discovery). From there
we outline the elements of the attenuation exception as relevant to
the disposition of this case. And we conclude this section by out-
lining the approaches that various lower courts (state and federal)
have taken in cases involving the attenuation doctrine and the
discovery of an outstanding arrest warrant.
                       A. The Rule and its Exceptions
  ¶15 The Fourth Amendment protects against unreasonable
searches and seizures. See U.S. CONST. amend. IV. The exclusion-
ary rule is a judicial remedy that gives life to that protection. In its
most basic terms, the exclusionary rule suppresses the admission
of evidence obtained in violation of the Constitution. See Mapp v.
Ohio, 367 U.S. 643, 655 (1961). It is a prudential doctrine, created
by courts to “compel respect for the constitutional guaranty.” Da-
vis v. United States, __ U.S. __, 131 S. Ct. 2419, 2426 (2011) (citations
omitted). There is no constitutional right to exclusion, nor is the
doctrine designed to redress the injury occasioned by a Fourth
Amendment violation. Id. (internal quotation marks omitted). The
exclusionary rule’s “sole purpose . . . is to deter future Fourth
Amendment violations.” Id.
  ¶16 While deterrent value is a “necessary condition for exclu-
sion,” it is “not a sufficient one.” Id. at 2427 (internal quotation
marks omitted). Exclusion of otherwise-relevant and probative
evidence from criminal proceedings “exacts a heavy toll on both
the judicial system and society at large.” Id. at 2427. The rule, after
all, often “suppress[es] the truth and set[s] the criminal loose in
the community without punishment.” Id. at 2427 (internal quota-
tion marks omitted).
 ¶17 The terms and conditions of the exclusionary rule must ap-
propriately account for these concerns. Thus, “[f]or exclusion to be
appropriate, the deterrence benefits of suppression must out-
weigh its heavy costs.” Id.
  ¶18 The exclusionary rule is far from absolute. In the simplest
case for exclusion, evidence is “direct or primary in its relation-
ship to the [police action].” 3 WAYNE R. LAFAVE ET AL., CRIMINAL
PROCEDURE, § 9.3(a) (3d ed. 2007) (internal quotation marks omit-
ted). In those cases, the connection between the illegal police ac-
tion and the evidence is clear and close. In other cases, the chal-
lenged evidence is less directly connected to the illegality, but is

                                   6
                         Cite as: 2015 UT 2
                       Opinion of the Court

“secondary or derivative in character.” Id. (describing as “second-
ary” or “derivative,” examples such as “physical evidence located
after an illegally obtained confession, or an in-court identifica-
tion . . . made following an illegally conducted pretrial identifica-
tion”). In these cases, there is a disconnect—factual, legal, or tem-
poral—between the unconstitutional conduct and the evidence.
These disconnects give rise to a series of exceptions to the exclu-
sionary rule.
  B. Independent Source, Inevitable Discovery, and Attenuation
  ¶19 Evidence seized as a result of an illegal search or seizure
may be admitted under three “closely related but analytically dis-
tinct” exceptions to the exclusionary rule: (1) the independent
source exception, (2) the inevitable discovery exception, and (3)
the attenuation exception. United States v. Terzado-Madruga, 897
F.2d 1099, 1113 (11th Cir. 1990).
  ¶20 Under the independent source doctrine, the “taint” that is
otherwise-attached to the fruit of police misconduct is removed
when the same fruit is derived from lawful police activity. See
Murray v. United States, 487 U.S. 533, 537 (1988). In the classic in-
dependent source scenario, “an unlawful entry has given investi-
gators knowledge of facts x and y, but fact z has been learned by
other means.” Id. at 538. In Segura v. United States, 468 U.S. 796,
800–01 (1984), for example, drug enforcement agents unlawfully
entered defendant’s apartment and remained there until a search
warrant was obtained. The United States Supreme Court deemed
the evidence acquired pursuant to the valid, untainted warrant
admissible because it was discovered pursuant to an “independ-
ent source.” Id. at 813–14.
  ¶21 This exception has also been extended to circumstances
where the fruit obtained through an independent source was itself
previously obtained unlawfully—“that is, in the example just giv-
en, to knowledge of facts x and y,” and not just z. Murray, 487 U.S.
at 538. In Murray, drug enforcement agents entered a warehouse
unlawfully and observed burlap-wrapped bales of marijuana, but
then subsequently seized the same evidence upon execution of a
valid search warrant. Assuming the agents “would have sought a
warrant [even] if they had not earlier entered the warehouse” (a
matter not resolved on the record in Murray and thus meriting a
remand), the Supreme Court held that the execution of the war-


                                 7
                          STATE v. STRIEFF
                       Opinion of the Court

rant would remove the taint of the earlier unlawful entry. Id. at
542–43 (noting that the search pursuant to the warrant would not
have been a “genuinely independent source . . . if the agents’ de-
cision to seek the warrant was prompted by what they had seen
during the initial entry, or if information obtained during that en-
try was presented to the Magistrate and affected his decision to
issue the warrant”) (footnote omitted).
  ¶22 The independent source doctrine thus turns on cause-in-
fact analysis. A source is independent—in a manner removing the
taint arising from a prior act of police misconduct—if it actually
led to the discovery of the evidence in question and would have
done so even in the absence of police misconduct. Where that is
the case, there is no longer a sufficient deterrence-based justifica-
tion for exclusion:
       [T]he interest of society in deterring unlawful police
       conduct and the public interest in having juries re-
       ceive all probative evidence of a crime are properly
       balanced by putting the police in the same, not a
       worse, position that they would have been in if no po-
       lice error or misconduct had occurred . . . .When the
       challenged evidence has an independent source, ex-
       clusion of such evidence would put the police in a
       worse position than they would have been in absent
       any error or violation.
Nix v. Williams, 467 U.S. 431, 443 (1984) (emphasis added) (foot-
note omitted) (citations omitted).
  ¶23 The inevitable discovery doctrine is related. Here the clas-
sic case is Nix. In Nix, the defendant had made incriminating
statements in response to police investigation impinging on the
right to counsel—which statements led police to the discovery of a
victim’s dead body. Id. at 435. But the record also indicated that a
search had been underway that inevitably would have led to the
discovery of the victim’s body but for the defendant’s unlawfully
obtained statements. Id. at 448–50. And the Nix Court upheld the
admissibility of the fruit of the unlawful investigation based on an
inevitable discovery rationale—holding that “when, as here, the
evidence in question would inevitably have been discovered
without reference to the police error or misconduct, there is no



                                 8
                         Cite as: 2015 UT 2
                       Opinion of the Court

nexus sufficient to provide a taint and the evidence is admissible.”
Id. at 448.
  ¶24 Both the independent source doctrine and the inevitable
discovery exception are rooted in cause-in-fact analysis. The for-
mer forecloses exclusion when tainted fruits are actually obtained
through a truly independent source. The latter prescribes the
same result if the tainted evidence inevitably would have been dis-
covered by lawful means.
  ¶25 The attenuation exception is distinct. It turns not on cause-
in-fact analysis but on a question of legal cause. Thus, under Wong
Sun v. United States, 371 U.S. 471 (1963), and Brown v. Illinois, 422
U.S. 590 (1975), evidence that would not have been secured but for
an unlawful search or seizure is nonetheless admissible if the legal
nexus between the police misconduct and the challenged evidence
is sufficiently attenuated that any tainting of the evidence is dissi-
pated. Wong Sun, 371 U.S. at 487–88 (declining to “hold that all
evidence is ‘fruit of the poisonous tree’ simply because it would
not have come to light but for the illegal actions of the police”)
(emphasis added) (internal quotation marks omitted)).
   ¶26 In Wong Sun, federal drug agents arrested the defendant
without probable cause, but he returned to the station house sev-
eral days later and gave a voluntary confession. Id. at 491. The
Court ruled that drugs seized pursuant to the unlawful arrest
were properly excluded as fruit of a poisonous tree. Id. at 487 (not-
ing that “this is not the case envisioned by this Court where the
exclusionary rule has no application because the Government
learned of the evidence ‘from an independent source’”). As to the
confession, however, the Court held that it might escape exclusion
even if “it would not have come to light but for the illegal actions
of the police.” Id. at 488. Specifically, the Court held that the ad-
missibility of the confession should turn on “whether, granting
establishment of the primary illegality, the evidence to which in-
stant objection is made has been come at by exploitation of that
illegality or instead by means sufficiently distinguishable to be
purged of the primary taint.” Id. (internal quotation marks omit-
ted).
  ¶27 Ultimately, the Wong Sun Court held the confession admis-
sible under this standard. “On the evidence that Wong Sun had
been released on his own recognizance after a lawful arraignment,


                                  9
                          STATE v. STRIEFF
                       Opinion of the Court

and had returned voluntarily several days later to make the
statement,” the Court held “that the connection between the arrest
and the statement had ‘become so attenuated as to dissipate the
taint.’” Id. at 491.
  ¶28 The Wong Sun standard was extended in Brown. There, the
defendant was also arrested without probable cause and gave a
subsequent confession, but this time the confession came within
two hours after the arrest. Brown, 422 U.S. at 604. The Brown Court
found such a confession not to satisfy the fact-intensive, case-by-
case analysis called for under the attenuation doctrine. Id. at 604–
05. In so doing, however, the Court articulated three factors of rel-
evance to the analysis: the “temporal proximity of the arrest and
the confession”; the “presence of intervening circumstances”; and
the “purpose and flagrancy of the official misconduct.” Id. at 603–
04. These factors weighed in favor of exclusion in Brown because
the confession was given just two hours after the arrest without
any intervening event of any significance, and the arrest was pa-
tently illegal and undertaken “in the hope that something might
turn up.” Id. at 605.
  ¶29 The Court reached a similar conclusion in Kaupp v. Texas,
538 U.S. 626 (2003). There the Court applied the Brown factors and
found the defendant’s confession to be the fruit of his prior illegal
arrest. Id. at 633. In so doing the Court emphasized that (1) there
was “no indication . . . that any substantial time passed between
Kaupp’s removal from his home in handcuffs and his confession
after only 10 or 15 minutes of interrogation”; (2) at least some of
the six officers involved in taking him into custody “were con-
scious that they lacked probable cause to arrest”; and (3) “the
State ha[d] not even alleged ‘any meaningful intervening event’
between the illegal arrest and Kaupp’s confession.” Id. at 633.
  ¶30 Thus, the attenuation exception eschews the “but for” ap-
proach to causation that drives the independent source and inevi-
table discovery exceptions. See United States v. Ceccolini, 435 U.S.
268, 276 (1978) (noting that the Court has “declined to adopt a ‘per
se’ or ‘but for’ rule that would make inadmissible any evidence,
whether tangible or live-witness testimony, which somehow came
to light through a chain of causation that began with an illegal ar-
rest’). It instead endorses a more nuanced analysis akin to proxi-
mate causation. In asking whether the attenuation exception ap-
plies, we assess whether the causal chain has been broken by in-

                                 10
                         Cite as: 2015 UT 2
                       Opinion of the Court

tervening circumstances. 3 And we do so in the light of the exclu-
sionary rule’s deterrence function. Thus, we “mark the point at
which the detriment of illegal police action becomes so attenuated
that the deterrent effect of the exclusionary rule no longer justifies
its cost.” LAFAVE ET AL., supra , § 9.3(c)).
                    C. The Attenuation Factors
  ¶31 The Supreme Court has set out (and we have applied) a
three-factor test to guide the attenuation inquiry. The three factors
are: (1) the “temporal proximity” of the unlawful detention and
the discovery of incriminating evidence, (2) the presence of “in-
tervening circumstances,” and (3) the “purpose and flagrancy” of
the official misconduct. Brown, 422 U.S. at 603–04 (1975); State v.
Arroyo, 796 P.2d 684, 690 n.4 (Utah 1990).
  ¶32 The threshold inquiry for attenuation analysis concerns the
existence of “intervening circumstances.” Such circumstances are
those that establish a break in the legal chain of events leading to
the discovery of the evidence at issue. See United States v. Green,
111 F.3d 515, 522 (7th Cir. 1997). Thus, a circumstance is “inter-
vening” if it is so distinct from the threshold Fourth Amendment
violation that it can be said that the challenged evidence is not a
product of “exploitation” of the illegality but instead the result of
“‘means sufficiently distinguishable to be purged of the primary
taint.’” Wong Sun, 371 U.S. at 488 (internal quotation marks omit-
ted).
  ¶33 A prototypical intervening circumstance involves a volun-
tary act by the defendant, such as a confession or consent to
search given after illegal police action. A voluntary confession or
consent to search might be the but-for product of an unlawful
search or seizure, but exclusion is foreclosed where the defend-
ant’s voluntary act is sufficiently independent to break the legal
connection to the primary violation. Under the caselaw, the inde-
pendence of such voluntary acts is established, for example,
where the confession or consent comes well after termination of a


 3 See Albert W. Alschuler, Herring v. United States: A Minnow or a
Shark?, 7 OHIO ST. J. OF CRIM. LAW 463, 478-79 (2009) (noting the
Supreme Court’s use of attenuation as “refer[ring] to situations in
which the causal chain between a Fourth Amendment violation
and the seizure of evidence ha[s] been broken.”).

                                 11
                           STATE v. STRIEFF
                        Opinion of the Court

defendant’s illegal detention, after defendant’s consultation with
counsel, or as a spontaneous comment not in response to any po-
lice interrogation. See LAFAVE, supra, § 9.4(a). Increasingly, courts
have extended this principle to the discovery of an outstanding
arrest warrant, see infra ¶ 38 n.5, a question to which we will turn
shortly.
  ¶34 Under the governing standard set forth in Brown, the ques-
tion whether a particular circumstance is sufficiently “interven-
ing” to dissipate the taint associated with a primary Fourth
Amendment violation “must be answered on the facts of each
case.” Brown, 422 U.S. at 603. And that analysis, in turn, depends
on the relationship between the “intervening circumstance” fac-
tor, on one hand, and the “purpose and flagrancy” and “temporal
proximity” considerations, on the other.
  ¶35 Conduct is “purposeful” if it is “investigatory in design
and purpose and executed in the hope that something might turn
up.” United States v. Simpson, 439 F.3d 490, 496 (8th Cir. 2006) (in-
ternal quotation marks omitted). “Flagrant” conduct is that which
is obviously improper—so far beyond the bounds of the Fourth
Amendment that law enforcement must have seen it as unlawful
but chose to engage in it anyway. See id.
  ¶36 Generally, close “temporal proximity” between the illegali-
ty and discovery of the evidence weighs in favor of suppression.
See State v. Shoulderblade, 905 P.2d 289, 293 (Utah 1995). Thus, a
“brief time lapse” between a Fourth Amendment violation and
the evidence obtained may “indicate[] exploitation because the
effects of the misconduct have not had time to dissipate.” Id.
          D. Attenuation and Outstanding Arrest Warrants
  ¶37 To date, the United States Supreme Court’s attenuation
cases have all involved confessions made by unlawfully detained
individuals. 4 Thus, the question presented here—of the applicabil-

 4  See, e.g., Kaupp v. Texas, 538 U.S. 626, 633 (2003) (suppressing
defendant’s murder confession following unlawful arrest); Taylor v.
Alabama, 457 U.S. 687, 694 (1982) (excluding a confession after find-
ing insufficient attenuation); Dunaway v. New York, 442 U.S. 200,
219 (1979) (excluding a confession obtained after an unlawful ar-
rest); Brown v. Illinois, 422 U.S. 590, 605 (1975) (holding that a con-
fession was sufficiently attenuated); Wong Sun v. United States, 371

                                  12
                         Cite as: 2015 UT 2
                       Opinion of the Court

ity of the attenuation doctrine to the discovery of an outstanding
arrest warrant in the course of an unlawful arrest or detention—is
a matter heretofore left to the lower courts.
  ¶38 Three principal approaches have emerged on this issue.
One set of decisions, exemplified by United States v. Green, 111
F.3d at 522, concludes that an outstanding arrest warrant may
qualify as “an even more compelling case” for an “intervening
circumstance” than a voluntary confession. Id. 5 The threshold ba-
sis for this determination in Green was the assertion that “[i]t
would be startling to suggest that because the police illegally
stopped an automobile, they cannot arrest an occupant who is
found to be wanted on a warrant—in a sense requiring an official
call of ‘Olly, Olly, Oxen Free.’” Id. at 521. In addition, the Green
court suggested that an outstanding warrant is in some sense
more independent of lawful police activity than a voluntary con-
fession. The basis for that conclusion was the assertion that “[a]ny
influence the unlawful stop would have on the defendant’s con-


U.S. 471, 478–79 (1963) (excluding evidence of narcotics obtained
through unlawfully obtained and tainted confession).
  This is a complete list of United States Supreme Court cases ap-
plying the attenuation doctrine. But it is certainly not an exhaus-
tive list of cases in which the Court has employed the term “at-
tenuation” in framing the exclusionary rule. That term has been
used in reference to a general principle of causation, in connection
with other principles of and exceptions to the exclusionary rule.
See Hudson v. Michigan, 547 U.S. 586, 593 (2006) (holding that a vi-
olation of the knock-and-announce rule was sufficiently attenuat-
ed); United States v. Leon, 468 U.S. 897, 911 (1984) (stating that the
police misconduct and the evidence of crime “may be sufficiently
attenuated” to be admissible); Segura v. United States, 468 U.S. 796,
805 (1984) (explaining the inevitable discovery doctrine in general
attenuation terms).
 5 See United States v. Simpson, 439 F.3d 490, 495 (8th Cir. 2006)
(adopting Green’s “compelling case” language); State v. Hill, 725
So.2d 1282, 1287 (La. 2008) (stating that the discovery of outstand-
ing warrants was a “significant intervening event”); Hardy v.
Commonwealth, 149 S.W.3d 433, 436 (Ky. App. 2004) (holding that
the intervening circumstance of the outstanding warrant “out-
weighed any possible [police] misconduct”).

                                 13
                           STATE v. STRIEFF
                        Opinion of the Court

duct is irrelevant,” and thus that “there is less ‘taint’ than in the
cases already recognized by the Supreme Court and this and other
circuits as fitting within the intervening circumstances exception.
Id. at 522. Thus, the Green court extended the attenuation doctrine
to a case involving the discovery of an outstanding warrant in the
course of an unlawful arrest.6 It did so on the basis of its conclu-
sion that the “purpose” of the stop in question was not to seek ev-
idence against the defendant in question (Green) but “to obtain
evidence against” a third party (Williams), and that there was “no
evidence of bad faith on the part of the police,” or any indication
that “the police exploit[ed] the stop in order to search [Green’s]
automobile.” Id. at 523. 7


 6  Within this first approach to attenuation, there appears to be
two lines of cases. One line expressly characterizes the discovery
of an outstanding warrant as a “compelling case” for an interven-
ing circumstance (as in Green). See, e.g., Simpson, 439 F.3d at 496
(holding that defendant’s outstanding arrest warrant constituted
an “extraordinary intervening circumstance”); People v. Murray,
728 N.E.2d 512, 516 (Ill. App Ct. 2000) (adopting Green’s analysis
as “instructive”). A second line deems the outstanding warrant a
dispositive consideration, but without any express characteriza-
tion of the warrant as a “compelling” or “extraordinary” interven-
ing circumstance. See, e.g., McBath v. State, 108 P.3d 241, 248–49
(Alaska Ct. App. 2005); People v. Brendlin, 195 P.3d 1074, 1080 (Cal.
2008); People v. Hillyard, 589 P.2d 939, 941 (Colo. 1979); State v. Fri-
erson, 926 So. 2d 1139, 1144 (Fla. 2006); State v. Cooper, 579 S.E.2d
754, 758 (Ga. App. 2003); State v. Page, 103 P.3d 454, 460 (Idaho
2004); Quinn v. State, 792 N.E.2d 597, 602 (Ind. Ct. App. 2003);
State v. Martin, 179 P.3d 457, 458–63 (Kan. 2008); Hill, 725 So.2d at
1285; Cox v. State, 916 A.2d 311, 323 (Md. 2007); People v. Reese, 761
N.W.2d 405, 412 (Mich. Ct. App. 2008); State v. Grayson, 336
S.W.3d 138, 147 (Mo. 2011) (en banc); State v. Thompson, 438
N.W.2d 131, 137 (Neb. 1989); Jacobs v. State, 128 P.3d 1085, 1089
(Okla. Crim. App. 2006); State v. Dempster, 434 P.2d 746, 748 (Or.
1967) (abrogated by State v. Bailey, 338 P.3d 702 (Or. 2014); Lewis v.
State, 915 S.W.2d 51, 54 (Tex. Ct. App. 1995).
 7  See also Page, 103 P.3d at 459 (finding attenuation in conjunc-
tion with a conclusion that police conduct was neither flagrant nor
motivated by an improper purpose); Quinn, 792 N.E.2d at 602

                                  14
                          Cite as: 2015 UT 2
                        Opinion of the Court

  ¶39 A second set of cases deems the discovery of an outstand-
ing warrant a matter of “‘minimal importance’” under the attenu-
ation factors set out in Brown, and thus carefully limits the doc-
trine’s applicability in the warrant scenario. See State v. Moralez,
300 P.3d 1090, 1102 (Kan. 2013). 8 These cases are motivated by the
concern that “[w]ere it otherwise, law enforcement officers could
randomly stop and detain citizens, request identification, and run
warrants checks despite the lack of any reasonable suspicion to
support the detention.” Id. at 1102. 9 And they narrowly circum-
scribe the applicability of the attenuation doctrine by concluding
that (a) the short time between an unlawful detention and a search
incident to an arrest on an outstanding warrant “weighs heavily”




(finding “no evidence suggesting any impropriety as the purpose
for stopping Quinn”).
 8  See also United States v. Gross, 662 F.3d 393, 404–06 (6th Cir.
2011) (holding that the discovery of a valid warrant is a factor but
is not “dispositive”); State v. Bailey, 338 P.3d 702, 704 (Or. 2014) (en
banc) (overruling prior precedent establishing a per se rule that
outstanding warrants attenuate taint and concluding that “the
weight assigned to the discovery of the arrest warrant depends on
the degree to which it was the direct consequence or objective of
the unlawful detention”); State v. Mazuca, 375 S.W.3d 294, 306
(Tex. Crim. App. 2012) (holding that the discovery of an outstand-
ing arrest warrant “should not be overemphasized to the ultimate
detriment of the goal of deterrence that animates the exclusionary
rule”).
 9  See also People v. Padgett, 932 P.2d 810, 816–17 (Colo. 1997)
(holding that the subsequent discovery of a possible warrant did
not overcome the other factors favoring suppression); People v.
Mitchell, 824 N.E.2d 642, 650 (Ill. App. Ct. 2005) (justifying the re-
fusal to extend the attenuation doctrine on the ground that sup-
pression “appears to be the only way to deter police from ran-
domly stopping citizens for the purpose of running warrant
checks”); State v. Soto, 179 P.3d 1239, 1244–45 (N.M. Ct. App. 2008)
(relying on Mitchell, holding that an outstanding warrant did not
sufficiently remove the taint of the initial unlawful conduct).

                                  15
                          STATE v. STRIEFF
                       Opinion of the Court

against attenuation, 10 and (b) an improper detention followed by a
warrant search “often will[] demonstrate at least some level of fla-
grant conduct”—of an “investigatory detention[] designed and
executed in the hope that something might turn up”—even if “the
detention is brief and the officers are courteous,” id. at 1103.
  ¶40 The third approach to the attenuation doctrine takes the se-
cond a step further. Under this third approach, an outstanding
warrant is less than a factor of “minimal importance” under the
attenuation doctrine; it is a matter that just doesn’t implicate the
doctrine at all. This approach was articulated in a dissenting opin-
ion in State v. Frierson, 926 So.2d 1139 (Fla. 2006) (Pariente, C.J.,
dissenting). In the Frierson case, Chief Justice Pariente proposed to
limit the attenuation doctrine to its original basis—to cases involv-
ing voluntary confessions resulting from an independent act of a
defendant’s “free will”—and thus to decline to extend it to cir-
cumstances involving the discovery of an outstanding warrant. Id.
at 1149–50 (relying on Brown’s articulation of the attenuation doc-
trine in terms of “whether a confession [that] is the product of a
free will” can be deemed an “intervening event” cutting off the
causal connection to the unlawful arrest). Because “the defend-
ant’s free will plays no role in the discovery of evidence in a
search incident to arrest pursuant to an active warrant discovered
during an illegal stop,” Chief Justice Pariente asserted that the lat-
ter circumstance “bears little resemblance to that of a defendant
who confesses or consents to a search for reasons that may be at-
tenuated from the illegality of the stop.” Id. at 1150. And the Fri-
erson dissent accordingly would have declined to extend the at-
tenuation doctrine to cases involving an unlawful detention lead-
ing to the discovery of an outstanding warrant, concluding that in
this scenario “[t]here is no break in the chain of circumstances
from the illegal detention to the discovery of evidence in the form
of an act of free will on the part of the defendant.” Id. at 1151.


 10  See also Padgett, 932 P.2d at 816–17 (stating that the evidence
was obtained directly as a result of the unlawful stop “without
sufficient intervening time and circumstances to carry the prose-
cutions’ burden of proof to demonstrate dissipation of the taint”);
Bailey, 338 P.3d at 713 (stating that the short time between the un-
lawful detention and the discovery of the challenged evidence
makes it “less likely” to “break . . . the causal chain”).

                                 16
                              Cite as: 2015 UT 2
                             Opinion of the Court

                 III. Attenuation as Applied to This Case
  ¶41 The threshold question presented concerns the applicabil-
ity of the attenuation doctrine to cases involving the discovery of
an outstanding warrant in the course of an unlawful detention.
Strieff urges a view of attenuation along the lines of the Frierson
dissent described above, asking us to restrict the doctrine to cir-
cumstances involving an independent act of a defendant’s “free
will” in confessing to a crime or consenting to a search. And be-
cause the discovery of an outstanding warrant is not an inde-
pendent act of free will but a direct result of an unlawful deten-
tion, Strieff asks us to deem the attenuation doctrine inapplicable.
  ¶42 We reverse on that basis. For a number of reasons, we con-
clude that attenuation is limited to the circumstances of the cases
embracing this doctrine in the Supreme Court—involving a de-
fendant’s independent acts of free will. And in the distinct cir-
cumstance involving the discovery of an outstanding warrant, we
conclude that a different doctrine—the inevitable discovery excep-
tion—controls.
  ¶43 The origins of attenuation are in cases involving independ-
ent acts of criminal defendants. Wong Sun, Brown, and Kaupp all
involved a confession given by a defendant after an initial unlaw-
ful arrest. 11 And the logic and terms of the attenuation doctrine
developed in these cases are focused on separating the initial po-
lice illegality from the subsequent, independent acts of a defend-
ant.
  ¶44 The seminal decision in Brown speaks in terms of whether a
defendant’s “statements (verbal acts, as contrasted with physical
evidence) were of sufficient free will as to purge the primary taint
of the unlawful arrest.” 422 U.S. 590, 600 (1975). And the Brown
Court quoted Wong Sun’s formulation of the central inquiry under
the attenuation doctrine in parallel terms—of whether a defend-
ant’s voluntary statement was “‘sufficiently an act of free will to
purge the primary taint’” of the unlawful arrest. Id. at 602 (quot-
ing Wong Sun v. United States, 371 U.S. 471, 486–87 (1963)).
  ¶45 The significance of a defendant’s independent act of “free
will” is also arguably inherent in the proximate cause premises of
the Brown formulation. Attenuation is focused on intervening cir-

 11   See supra ¶ 37, n.4.

                                     17
                          STATE v. STRIEFF
                       Opinion of the Court

cumstances sufficient to break the proximate connection to the ini-
tial violation of the Fourth Amendment. An intervening cause is a
“means sufficiently distinguishable” from the threshold illegality
that the taint of the initial violation is purged. Hudson v. Michigan,
547 U.S. 586, 592 (2006) (internal quotation marks omitted). The
terminology is significant. In proximate cause parlance, an inter-
vening cause is a subsequent, independent occurrence that materi-
ally contributes to the result. See McCorvey v. Utah State Dep’t. of
Transp., 868 P.2d 41, 45 (Utah 1993); RESTATEMENT (SECOND) OF
TORTS § 442 (1965). Such a cause cuts off the legal causal connec-
tion to the act of an initial tortfeasor where the intervening cause
is not foreseeable (and is thus a superseding cause). See Cruz v. Mid-
dlekauff Lincoln-Mercury, Inc., 909 P.2d 1252, 1257 (Utah 1996).
  ¶46 This concept cannot easily be extended to the discovery of
an outstanding warrant. The discovery of an outstanding warrant
is hardly an independent act or occurrence. It is part of the natu-
ral, ordinary course of events arising out of an arrest or detention.
And in that sense, even if the warrant could be thought of as
somehow intervening, it would hardly be unforeseeable. So to the
extent the attenuation doctrine is about proximate cause, see supra
¶ 45, an outstanding warrant does not qualify, as it is not an inde-
pendent act that is sufficiently removed from the primary illegali-
ty to qualify as intervening.
  ¶47 The attenuation factors articulated by the Supreme Court
also seem to cut in the same direction. First, consideration of the
“temporal proximity of the arrest and the confession,” Brown, 422
U.S. at 603, reinforces the centrality of proximate cause analysis. If
an extended time lapse is a plus factor for attenuation—as it clear-
ly is as the test has been formulated—the focus must necessarily
be on independent acts removed from the primary act of police
misconduct. Indeed, applying this factor to the discovery of an
independent warrant would turn the inquiry on its head. In the
context of an unlawful detention followed by a warrants check,
temporal delay would logically count in favor of the government.
The constitutional violation in a Terry stop, after all, is a product
of the unreasonable delay associated with an individual’s deten-
tion by the government. See United States v. Sharpe, 470 U.S. 675,
686 (1985). So the government could hardly assert the lack of
“temporal proximity” in the discovery of a search warrant as a



                                 18
                         Cite as: 2015 UT 2
                       Opinion of the Court

basis for attenuation (and thus avoidance of the exclusionary
rule).
  ¶48 Second, the Brown Court’s formulation of the “purpose and
flagrancy” factor is also ill-suited to the outstanding warrant sce-
nario. In Brown, the Court’s application of this factor was focused
on the “manner in which [the defendant’s] arrest was affected,”
with particular attention to whether that “manner” gave “the ap-
pearance of having been calculated to cause surprise, fright, and
confusion.” 422 U.S. at 605. This, again, is an outgrowth of the in-
quiry into proximate causation, as a purposeful attempt at “sur-
prise, fright, and confusion” could predictably yield a confession
that would be entirely foreseeable (and thus connected to—and
hardly independent of—the primary police misconduct). And that
assessment would have little application to the outstanding war-
rant scenario, where “surprise, fright, and confusion” are utterly
irrelevant.
  ¶49 These are indications that the Supreme Court’s attenuation
doctrine is directed only at intervening circumstances involving a
defendant’s independent acts of free will (such as a confession
and perhaps a consent to search). An even stronger signal appears
in the terms of a parallel doctrine, the inevitable discovery excep-
tion. As noted above, this exception exempts from exclusion evi-
dence that is the but-for result of police misconduct but that also
would inevitably have been produced by untainted police work.
See Nix v. Williams, 467 U.S. 431, 448–50 (1984). This doctrine is di-
rectly implicated in a case like this one, involving two parallel acts
of police work—one a violation of the Fourth Amendment (deten-
tion without reasonable suspicion) and the other perfectly legal
(execution of an outstanding arrest warrant). See State v. Topanotes,
2003 UT 30, ¶ 22, 76 P.3d 1159 (holding, in a case involving an un-
lawful detention leading to the discovery of an outstanding war-
rant, that evidence uncovered in a search incident to arrest on the
warrant did not qualify under the inevitable discovery exception
and thus was subject to suppression). And extension of the atten-
uation doctrine to the outstanding warrant scenario would evis-
cerate the inevitable discovery exception.
  ¶50 That prospect is troubling. Ordinarily, where lawful police
work runs in tandem with an illegal parallel, the taint of the latter
is tough to eliminate. Under Nix, our law does not lightly excuse
an initial Fourth Amendment violation on the ground that it was

                                 19
                          STATE v. STRIEFF
                       Opinion of the Court

paralleled by a lawful investigation. Instead we insist on exclusion
unless the fruits of the lawful investigation would inevitably have
come about regardless of the unlawful search or seizure. That ap-
proach would require exclusion in this case, as our decision in the
Topanotes case indicates. See Topanotes, 2003 UT 30, ¶ 20–21.
Granted, Strieff was lawfully arrested on an outstanding arrest
warrant, and a search incident to arrest was thus also perfectly
appropriate.12 But given that that arrest and search came about as
a but-for result of his unlawful detention, exclusion would still be
required under Nix unless the contraband he possessed would in-
evitably have been discovered in the absence of the threshold un-
lawful detention. And such a showing would be difficult at best in
a case like this one, as we cannot know whether Strieff might ul-
timately have had this contraband in his possession on any future
date on which he may have been arrested on the outstanding war-
rant.
  ¶51 Extension of the attenuation doctrine to this scenario would
blur the lines of the inevitable discovery exception. If attenuation
is a free-wheeling doctrine unmoored from voluntary acts of a de-
fendant’s free will, then the limits of the Nix formulation of inevi-
table discovery would be substantially curtailed. If Brown, and not
Nix, prescribes the standard for lawful police conduct removing
the taint from unlawful acts, then inevitability would no longer be
the standard. Instead, it would be enough for the prosecution to
assert that an initial act of police misconduct was insufficiently
“purposeful and flagrant” and lacking in “temporal proximity” to
a lawful investigation to sustain exclusion.
  ¶52 No court has yet extended the attenuation doctrine this far.
To date, the courts that have deemed the Brown factors to apply to
the outstanding warrant scenario seem to treat a search incident to
an arrest on an outstanding warrant as a unique form of lawful
police work. But there is no logical reason to treat such a search
any differently from any other form of police work. So the logic of


 12  For this reason the professed concern about the lawfulness of
the arrest on the outstanding warrant, see Green v. United States,
111 F.3d 515, 521 (7th Cir. 1997), is a red herring. The exclusionary
rule (with its attendant exceptions) is about exclusion of evidence.
No one is contesting—or even could reasonably contest—the ar-
rest on the outstanding warrant.

                                 20
                         Cite as: 2015 UT 2
                       Opinion of the Court

the decisions extending Brown to the outstanding warrant scenar-
io will, if taken seriously, ultimately swallow the inevitable dis-
covery exception.
  ¶53 And even if these decisions are not taken to their logical
end, the resulting legal landscape (as it currently stands in many
jurisdictions) is untenable. Under the prevailing law in an increas-
ing number of jurisdictions, one form of lawful police work (a
search incident to an arrest on an outstanding warrant) is favored
above all others (such as the completion of an outstanding inves-
tigation, as in Nix). This is equally problematic. A search incident
to arrest on an outstanding warrant has no favored status under
the Fourth Amendment. It is entirely arbitrary to subject most
lawful police work (pursued in tandem with unlawful activity) to
the high bar of inevitable discovery while lowering the bar for ar-
rests incident to an outstanding warrant.
  ¶54 We cannot adopt this premise without overriding the Nix
formulation of the inevitable discovery exception. And because
we construe the Brown formulation of attenuation to be limited to
cases involving a defendant’s independent acts of free will, we
deem the attenuation doctrine inapplicable here, and reverse the
court of appeals on that basis. We therefore hold that Strieff was
entitled to suppression of the evidence secured in the search inci-
dent to his arrest in this case, as the attenuation doctrine advanced
by the State in opposition to that motion was not a viable excep-
tion to the exclusionary rule in this case.
                           IV. Conclusion
  ¶55 The terms and conditions of the exclusionary rule have
been meted out by the Supreme Court in a piecemeal, common-
law fashion. 13 On matters not yet addressed by that Court, the
lower courts are left to fill in the gaps. This case implicates a gap
of substantial significance. And the courts that have addressed it
have come to substantially different conclusions.
  ¶56 The confusion, in our view, stems from a threshold misun-
derstanding of the scope of attenuation. Thus, the reason the
courts have struggled to arrive at a consensus formulation of at-

 13 See Omar Saleem, The Age of Unreason: The Impact of Reasona-
bleness, Increased Police Force, and Colorblindness on Terry “Stop and
Frisk”, 50 OKLA. L. REV. 451, 460 (1997).

                                 21
                         STATE v. STRIEFF
                      Opinion of the Court

tenuation as applied to the outstanding warrant scenario is that
the doctrine has no application in this circumstance. In the ab-
sence of guidance from the United States Supreme Court, courts
such as ours are left with only tea leaves. We are mindful, in to-
day’s effort to fill this gap in Fourth Amendment law, of the dis-
tinct doctrines of attenuation and inevitable discovery. To pre-
serve the analytical distinction between the two, attenuation
should be limited to cases involving intervening acts of a defend-
ant’s free will. That holding, which we adopt today, avoids the
analytical dilemmas that are currently troubling the lower courts
(as to whether an outstanding warrant is of “compelling” or “min-
imal” importance, as to the significance of the “temporal proximi-
ty” factor, and as to the application of the “purpose and flagran-
cy” factors). Ultimately, the United States Supreme Court may
chart a different course. Such is its constitutional prerogative.
Ours is to make sense of and apply existing precedent, to fill in
gaps by reading any and all tea leaves available to us.
                            ———————




                               22
