Court Opinion

ID: 4699497
Source: CourtListenerOpinion
Date Created: 2021-06-29 15:22:15.382825+00
Date Added: 2024-06-11T08:06:03.368697
License: Public Domain

2021 WI 68

                  SUPREME COURT         OF   WISCONSIN
CASE NO.:              2019AP1404-CR

COMPLETE TITLE:        State of Wisconsin,
                                 Plaintiff-Respondent,
                            v.
                       George Steven Burch,
                                 Defendant-Appellant.

                          ON CERTIFICATION FROM THE COURT OF APPEALS

OPINION FILED:         June 29, 2021
SUBMITTED ON BRIEFS:
ORAL ARGUMENT:         April 12, 2021

SOURCE OF APPEAL:
   COURT:              Circuit
   COUNTY:             Brown
   JUDGE:              John Zakowski

JUSTICES:
HAGEDORN, J., delivered the majority opinion of the Court, in
which ZIEGLER, C.J, ROGGENSACK, and REBECCA GRASSL BRADLEY, JJ.,
joined, and in which DALLET and KAROFSKY, JJ., joined with
respect to Parts I. and II.B. REBECCA GRASSL BRADLEY, J., filed
a concurring opinion. DALLET, J., filed an opinion concurring
in part and dissenting in part, in which KAROFSKY, J., joined
and in which ANN WALSH BRADLEY, J., joined except for footnote
1. ANN WALSH BRADLEY, J., filed a dissenting opinion.
NOT PARTICIPATING:

ATTORNEYS:

       For the defendant-appellant, there were briefs filed by Ana
L. Babcock and Babcock Law, LLC. There was an oral argument by
Ana L. Babcock.

       For the plaintiff-respondent, there was a brief filed by
Aaron R. O’Neil, assistant attorney general; with whom on the
brief was Joshua L. Kaul, attorney general. There was an oral
argument by Aaron R. O’Neil.
    An amicus curiae brief was filed on behalf of Legal Action
of Wisconsin, Inc. by Rebecca M. Donaldson, Milwaukee.

                                2
                                                                     2021 WI 68
                                                                     NOTICE
                                                       This opinion is subject to further
                                                       editing and modification.   The final
                                                       version will appear in the bound
                                                       volume of the official reports.
No.    2019AP1404-CR
(L.C. No.   2016CF1309)

STATE OF WISCONSIN                                 :             IN SUPREME COURT

State of Wisconsin,

            Plaintiff-Respondent,                                         FILED
      v.                                                             JUN 29, 2021
George Steven Burch,                                                    Sheila T. Reiff
                                                                     Clerk of Supreme Court
            Defendant-Appellant.

HAGEDORN, J., delivered the majority opinion of the Court, in
which ZIEGLER, C.J, ROGGENSACK, and REBECCA GRASSL BRADLEY, JJ.,
joined, and in which DALLET and KAROFSKY, JJ., joined with
respect to Parts I. and II.B. REBECCA GRASSL BRADLEY, J., filed
a concurring opinion.   DALLET, J., filed an opinion concurring
in part and dissenting in part, in which KAROFSKY, J., joined
and in which ANN WALSH BRADLEY, J., joined except for
footnote 1. ANN WALSH BRADLEY, J., filed a dissenting opinion.

      APPEAL    from    a   judgment    of   the       Circuit     Court     for    Brown

County.     Affirmed.

      ¶1    BRIAN      HAGEDORN,   J.    George        Steven      Burch     appeals      a

judgment of conviction for first-degree intentional homicide on

the   grounds     that      two    pre-trial       evidentiary          motions       were
incorrectly denied.
                                                                    No.     2019AP1404-CR

       ¶2   First, relying on the Fourth Amendment, Burch moved to

suppress the admission of incriminating cell phone data.                            This

data was obtained via an unrelated criminal investigation and

kept in a police database.               A different law enforcement agency

investigating the homicide came upon this data and used it to

connect Burch to the homicide.                  Burch argues that the initial

download of the data exceeded the scope of his consent, the data

was unlawfully retained, and the subsequent accessing of the

data    violated       his   reasonable         expectation    of     privacy.        We

conclude that even if some constitutional defect attended either

the initial download or subsequent accessing of the cell phone

data, there was no law enforcement misconduct that would warrant

exclusion of that data.                 Therefore, we conclude the circuit

court correctly denied Burch's motion to suppress that data.

       ¶3   Regarding        the   second       pre-trial     evidentiary       motion,

Burch   asks    us     to    reverse    the     circuit     court's       discretionary

decision to admit evidence from a Fitbit device allegedly worn

by the victim's boyfriend at the time of the homicide.                              This
evidence,      Burch    maintains,       should     have    been    accompanied       by

expert testimony and was insufficiently authenticated.                         We agree

with the State that the circuit court's decision to admit this

evidence was not an erroneous exercise of discretion.                           Burch's

judgment of conviction is affirmed.

                                   I.    BACKGROUND

       ¶4   On May 20, 2016, Nicole VanderHeyden went to a bar
with her boyfriend, Douglass Detrie.                  The two became separated
                                            2
                                                                         No.     2019AP1404-CR

and, in the course of a subsequent phone call and text messages,

got into an argument.              Detrie returned alone to their shared

home.       The next day, VanderHeyden's body was discovered next to

a nearby field.             Her blood-stained clothing was later found

discarded alongside a freeway on-ramp, and some of her blood and

hair       were    identified     outside          the     house    of     VanderHeyden's

neighbor.          The Brown County Sheriff's Office (the "Sheriff's

Office") opened a homicide investigation that spanned the next

several months.         Detrie was initially a suspect, but the focus

of the investigation shifted away from Detrie in part because

his    Fitbit      device   logged      only       12    steps    during   the       hours   of

VanderHeyden's death.1

       ¶5        While the Sheriff's Office investigated VanderHeyden's

homicide,         the   Green     Bay     Police          Department       (the        "Police

Department")        undertook     an    unrelated          investigation         into    three

incidents involving the same vehicle——a stolen vehicle report, a

vehicle fire, and a hit-and-run.                    George Burch was a suspect in

this       investigation,        and    Police           Department      Officer        Robert
Bourdelais        interviewed     him    on        June    8,    2016.         Burch    denied

involvement and offered the alibi that he was at a bar that

night      and    texting    a   woman     who          lived    nearby.        As     Officer

Bourdelais testified, "I asked [Burch] if I could see the text

messages between him and [the woman], if my lieutenant and I

could take a look at his text messages."                         Burch agreed.         Officer

       Detrie wore a Fitbit Flex, a wrist-worn device that
       1

continuously tracks the wearer's steps and interfaces with the
wearer's phone or computer.

                                               3
                                                                         No.     2019AP1404-CR

Bourdelais         then    explained       that       he     preferred         to     download

information off the phone because "it's a lot easier to do that

than try to take a bunch of pictures and then have to scan those

in."     "So I asked him if he would be willing to let me take his

phone to this detective, download the information off the phone

and then I'd bring the phone right back to him . . . and he said

that would be fine."

       ¶6     Before      Officer        Bourdelais         took   the     phone       to   be

downloaded, Burch signed a consent form.                           The form read:           "I

George       Stephen      Burch . . . voluntarily             give    Det.          Danielski,

Officer      Bourdelais      or    any     assisting        personnel      permission       to

search my . . . Samsung cellphone."                   Officer Bourdelais took the

phone and the signed consent form to the certified forensic

computer      examiner      for    the     Police     Department.              The    forensic

expert performed a "physical extraction" of all the data on

Burch's phone, brought the data into a readable format, and

saved       the    extraction      to    the       Police    Department's            long-term

storage.          At a motion hearing, the forensic expert testified
that this was consistent with the Police Department's standard

practice.

       ¶7     Two    months       later,    two      Sheriff's       Office         detectives

continuing the investigation of VanderHeyden's homicide matched

a DNA sample from VanderHeyden's sock to Burch.                           The detectives

then searched their own department's records and the records of

other local departments for prior police contacts with Burch.

There they discovered the Police Department's file related to
the three vehicle-related incidents.                       The file included Burch's
                                               4
                                                                                 No.       2019AP1404-CR

signed consent form and a copy of the data the Police Department

extracted      from       Burch's       phone       during         the    search.             It    also

contained      a    narrative           written          by    Officer         Bourdelais          which

indicated Burch said Officer Bourdelais "could take his phone to

the    department         to     have       the    information           on     it     downloaded."

Nothing in the consent form, the narrative, or anything else in

the file, indicated that Burch limited the scope of the data he

consented to have downloaded from his phone.

       ¶8     The    Sheriff's          Office          detectives        reviewed           the     data

downloaded from Burch's phone.                      They noted that Burch's internet

history       included           64      viewings             of    news         stories           about

VanderHeyden's death.                 And they also discovered Burch had an

email address associated with a Google account.                                        In light of

this    discovery,         the     Sheriff's            Office      detectives          procured       a

search warrant to obtain the "Google Dashboard" information from

Google corresponding to Burch's email address.                                   The data Google

provided      contained          location          information           that    placed        Burch's

phone at a bar VanderHeyden visited the night of her death, a
location      near        VanderHeyden's                residence,         the         place       where

VanderHeyden's            body        was     found,          and        the      on-ramp          where

VanderHeyden's discarded clothing was discovered.

       ¶9     Burch   was        arrested          and    charged         with       VanderHeyden's

death.       He filed two pre-trial evidentiary motions relevant to

this appeal.

       ¶10    In    one    motion,          Burch       sought      to     suppress          the   data

obtained from his cell phone for two reasons:                                     (1) the Police
Department's        extraction          of        the    data      exceeded          the     scope    of
                                                    5
                                                                          No.     2019AP1404-CR

Burch's consent by obtaining all the phone's data, rather than

just the text messages; and (2) the Sheriff's Office unlawfully

accessed the data in August 2016.                        The circuit court2 denied

Burch's    motion.          It    concluded       that       the   conversation       between

Burch and Officer Bourdelais did not limit the scope of Burch's

consent,    and   that       "the    sharing       of    such      information,       without

first    obtaining      a    warrant,      is      a    common      and    long-understood

practice between related departments."

     ¶11    Burch    also         moved    to      exclude         evidence       related     to

Detrie's Fitbit device.               He argued the State must produce an

expert to establish the reliability of the science underlying

the Fitbit device's technology and that the State failed to

sufficiently      authenticate         the        records.          The     circuit       court

disagreed and refused to exclude the Fitbit evidence related to

step-counting.3

     ¶12    Burch    testified        in     his       own    defense      at    trial.       He

denied killing VanderHeyden, but acknowledged he was with her

the night she died.              According to Burch, he met VanderHeyden at
a   bar,   and    the       two     left   together.               After        parking     near

VanderHeyden's house, they became intimate.                           That, Burch said,

was the last thing he remembered before waking up on the ground

with Detrie there, and VanderHeyden dead.                           Burch told the jury

that Detrie held him at gunpoint and instructed him to move

     2 The Honorable John P. Zakowski of the Brown County Circuit
Court presided.
     3 The circuit court granted Burch's motion in part, agreeing
to exclude Fitbit evidence related to sleep-monitoring.

                                              6
                                                                     No.    2019AP1404-CR

VanderHeyden's body into his vehicle, drive to a field, and

carry VanderHeyden's body into the ditch.                       Only then did Burch

escape   by    pushing     Detrie,    running         back    to    his    vehicle,    and

driving away.       Burch added that on his way home he noticed that

articles of VanderHeyden's clothing were still in his vehicle

and threw them out the window in a panic.                          In the months that

followed, Burch told no one this version of events, even as

authorities sought the public's help in solving VanderHeyden's

homicide.

    ¶13       The   jury     found      Burch          guilty       of     first-degree

intentional homicide, and the circuit court sentenced him to

life in prison.         Burch appealed, challenging the circuit court's

denial of his motion to suppress the cell phone data and his

motion to exclude the Fitbit evidence.                        The court of appeals

certified the case to us, and we accepted the certification.

                               II.     DISCUSSION

                             A.   Cell Phone Data
    ¶14       Burch asks us to reverse the circuit court's denial of

his motion to suppress the cell phone data as contrary to the

Fourth Amendment.         The Fourth Amendment protects the "right of

the people to be secure in their persons, houses, papers, and

effects,      against    unreasonable       searches         and    seizures."        U.S.

Const. amend. IV.          On review of a circuit court's denial of a

suppression motion, we uphold the circuit court's findings of

historical      fact     unless      they       are    clearly        erroneous,       and
independently apply constitutional principles to those facts.
                                            7
                                                                       No.     2019AP1404-CR

State     v.    Robinson,       2010     WI 80,       ¶22,    327    Wis. 2d 302,       786

N.W.2d 463.

      ¶15      Before    us,     Burch    argues       the    cell     phone     data   was

obtained in violation of the Fourth Amendment for three reasons:

(1) the Police Department obtained the data without his consent;

(2) the Police Department unlawfully retained the data after its

investigation into the vehicle-related incidents had ended; and

(3) the Sheriff's Office unlawfully accessed the data in the

Police Department's records without a warrant.4                        However, for the

reasons        that    follow,       regardless       of     whether    the     data    was

unlawfully obtained or accessed, we conclude suppression of the

data is not warranted under the exclusionary rule.                            See Herring

v.   United      States,       555     U.S. 135,      139    (2009)     (accepting      the

"assumption that there was a Fourth Amendment violation" and

analyzing whether the exclusionary rule applied); see also State

v. Kerr, 2018 WI 87, ¶¶20-24, 383 Wis. 2d 306, 913 N.W.2d 787.

                           1.        The Exclusionary Rule
      ¶16      "When    there    has     been    an    unlawful      search,     a   common

judicial       remedy    for     the    constitutional         error    is    exclusion."

State     v.    Dearborn,       2010     WI 84,       ¶15,    327    Wis. 2d 252,       786

      4Burch forfeited his argument related to the Police
Department's retention of the cell phone data by not raising
that argument before the circuit court.  See State v. Huebner,
2000 WI 59, ¶10, 235 Wis. 2d 486, 611 N.W. 2d 727.         His
arguments regarding the initial download of the data and the
subsequent accessing of the data are, however, properly before
us.

                                             8
                                                                  No.   2019AP1404-CR

N.W.2d 97.         The   exclusionary       rule   is    a   judicially-created,

prudential doctrine designed to compel respect for the Fourth

Amendment's constitutional guaranty.                 Davis v. United States,

564 U.S. 229, 236 (2011).             In recent years, the United States

Supreme Court has significantly clarified the purpose and proper

application of the exclusionary rule.                    See id.; Herring, 555

U.S. 135.      In Davis, the Supreme Court explained that prior

cases suggested that the exclusionary rule "was a self-executing

mandate implicit in the Fourth Amendment itself."                       564 U.S. at

237.      However, more recent cases have acknowledged that the

exclusionary rule is not one of "reflexive" application, but is

to be applied only after a "rigorous weighing of its costs and

deterrence benefits."          Id. at 238.         Thus, in both Herring and

Davis, the Court explained that to "trigger the exclusionary

rule,     police    conduct    must    be    sufficiently         deliberate    that

exclusion can meaningfully deter it, and sufficiently culpable

that such deterrence is worth the price paid by the justice

system."     Herring, 555 U.S. at 144; see also Davis, 564 U.S. at
240.

       ¶17   The "sole purpose" of the exclusionary rule "is to

deter future Fourth Amendment violations."                      Davis, 564 U.S. at

236-37.      Therefore, exclusion is warranted only where there is

some    present     police    misconduct,      and      where    suppression    will

appreciably deter that type of misconduct in the future.                       Id. at

237.    The exclusionary rule applies only to police misconduct

that can be "most efficaciously" deterred by exclusion.                          Id.
(quoting United States v. Calandra, 414 U.S. 338, 348 (1974)).
                                        9
                                                            No.   2019AP1404-CR

Specifically, "the exclusionary rule serves to deter deliberate,

reckless, or grossly negligent conduct, or in some circumstances

recurring or systemic negligence."              Herring, 555 U.S. at 144.

"But when the police act with an objectively reasonable good-

faith belief that their conduct is lawful, or when their conduct

involves   only     simple,    isolated       negligence,   the   deterrence

rationale loses much of its force, and exclusion cannot pay its

way."   Davis, 564 U.S. at 238 (cleaned up).

    ¶18    "Real deterrent value is a 'necessary condition for

exclusion,'   but   it   is   not   'a    sufficient'   one."     Id. at   237

(quoting Hudson v. Michigan, 547 U.S. 586, 596 (2006)).                     In

Davis, the Court explained that the "analysis must also account

for the 'substantial social costs' generated by the rule."                 Id.

(quoting United States v. Leon, 468 U.S. 897, 907 (1984)).                  It

elaborated:

    Exclusion exacts a heavy toll on both the judicial
    system and society at large.         It almost always
    requires   courts   to  ignore   reliable, trustworthy
    evidence bearing on guilt or innocence.       And its
    bottom-line effect, in many cases, is to suppress the
    truth and set the criminal loose in the community
    without punishment. Our cases hold that society must
    swallow this bitter pill when necessary, but only as a
    "last resort."    For exclusion to be appropriate, the
    deterrence benefits of suppression must outweigh its
    heavy costs.
Id. (citations omitted).

    ¶19    Applying this rationale, the Supreme Court in Herring

held that a county's failure to update a computer database to

reflect the recall of an arrest warrant was only negligent, and
therefore was "not enough by itself to require 'the extreme

                                         10
                                                                    No.       2019AP1404-CR

sanction of exclusion.'"              555 U.S. at 140 (quoting Leon, 468

U.S. at 916).       Similarly, in Davis, the Supreme Court refused to

exclude evidence that was obtained via a search conducted in

compliance with binding, but subsequently overruled, precedent.

564 U.S. at 232.            Exclusion, it explained, was inappropriate

because it "would do nothing to deter police misconduct."                             Id.

      ¶20   We have followed suit as well.                  In Kerr, we explained

that no police misconduct occurred when an officer conducted an

arrest relying on dispatch's confirmation that the defendant had

a warrant out for his arrest.               383 Wis. 2d 306, ¶22.               Exclusion

was   improper     because     "the    officers'       conduct          [was]    at     most

negligent,    and    isolated       negligence       is     not    'misconduct'          for

purposes of the exclusionary rule."                  Id. (citing Herring, 555

U.S. at 146-47).

      ¶21   Many     more     examples       could     be    provided,5          but     the

principle     is    clear:          unless       evidence         was        obtained       by

sufficiently       deliberate       and      sufficiently          culpable           police

misconduct,      "[r]esort     to     the    massive      remedy        of    suppressing

      5See, e.g., United States v. Leon, 468 U.S. 897, 916 (1984)
(reasonable reliance on a warrant later held invalid); Illinois
v. Krull, 480 U.S. 340, 342 (1987) (reasonable reliance on
subsequently invalidated statutes); Arizona v. Evans, 514
U.S. 1, 15-16 (1995) (reasonable reliance on arrest warrant
information in a database maintained by judicial employees);
State v. Ward, 2000 WI 3, ¶63, 231 Wis. 2d 723, 604 N.W.2d 517
(reasonable reliance on settled law subsequently overruled);
State v. Dearborn, 2010 WI 84, ¶44, 327 Wis. 2d 252, 786
N.W.2d 97 (refusing to exclude evidence where doing so "would
have absolutely no deterrent effect on officer misconduct").

                                            11
                                                                   No.    2019AP1404-CR

evidence of guilt is unjustified."6                 Hudson, 547 U.S. at 599.

With these principles in mind, we turn to the facts at hand.

                                 2.     Application

      ¶22    In this case, the Sheriff's Office detectives acted by

the book.        After a DNA sample from VanderHeyden's sock matched

Burch, officers checked the interdepartmental records already on

file with the police.7           They discovered the two-month-old Police

Department file documenting the investigation for the vehicle-

related     incidents.      In    it,     they   found      and   reviewed      Burch's

signed consent form and Officer Bourdelais' narrative further

documenting Burch's consent.               The Sheriff's Office detectives

observed that neither the consent form nor the narrative listed

any   limitations     to   the    scope    of    consent.         And    the   officers

reviewed the downloaded data, having every reason to think it

was lawfully obtained with Burch's unqualified consent.

      ¶23    Burch   argues      that    the    Sheriff's     Office      should   have

obtained     a   warrant   before       accessing     the    Police      Department's

      6Failure to apply exclusion is usually described in our
cases as the "good faith" exception to the exclusionary rule.
See, e.g., Dearborn, 327 Wis. 2d 252, ¶4.   However, the United
States Supreme Court has called the "good faith" label
confusing. Herring v. United States, 555 U.S. 135, 142 (2009).
The Supreme Court's most recent cases do not use that phrase as
a catchall for cases where exclusion is improper, and do not
describe their conclusion that exclusion was inappropriate as
applying a "good faith" exception. See id. at 147-48; Davis v.
United States, 564 U.S. 229, 249-50 (2011).
      7Officers from both the Police Department and the Sheriff's
Office testified that it is common police practice for agencies
to share records with other agencies.

                                          12
                                                                     No.     2019AP1404-CR

data.     But no case from this court or the federal courts has

suggested       that    accessing   evidence        previously       obtained        by    a

sister    law    enforcement    agency     is   a     new    search        triggering      a

renewed    warrant      requirement.8         Rather,       the   Sheriff's        Office

detectives reasonably relied on Burch's signed consent form and

Officer Bourdelais' narrative to conclude that Burch consented

to the download of the data.             They had no reason to think they

were engaging in illegal activity by reviewing interdepartmental

files and evidence.          Far from it.        Reliance on well-documented

computer records, like the detectives did here, is something the

Supreme Court has characterized as objectively reasonable police

conduct.        Arizona v. Evans, 514 U.S. 1, 15-16 (1995).                          Thus,

there    was    no     misconduct   that      would    "render[]           the   evidence

suppressible         under   the    exclusionary            rule."           Kerr,        383

Wis. 2d 306, ¶22.

    ¶24        Moreover, even if the Sheriff's Office's actions could

be labeled as some kind of misconduct, nothing they did would

rise beyond mere negligence.            See id., ¶22 (concluding that "to
the extent that looking at a warrant before executing it may be

    8  Justice Dallet's concurrence/dissent argues that courts
should treat cell phone data collected by law enforcement
differently than other types of evidence. It acknowledges that
the sharing of already-collected evidence without a warrant by
sister law enforcement agencies is routine and unproblematic,
but maintains a different kind of analysis should attend cell
phone evidence.   We need not decide this question to conclude
exclusion is not warranted in this case.        Justice Dallet's
approach   would   break   new   ground   in   Fourth   Amendment
jurisprudence, and as such, the violation of her new proposed
rule does not implicate the kind of gross or systemic law
enforcement misconduct the exclusionary rule is meant to deter.

                                         13
                                                                                No.     2019AP1404-CR

best       practice,"       failing       to     do    so    was    "at    most        negligent");

Herring, 555 U.S. at 140 (holding that a county's failure to

update      a   computer      database          was    negligent          and    therefore         "not

enough by itself to require" exclusion).                               And mere negligence

does not warrant suppression.                    Id. at 144-45.

       ¶25      In addition, the societal cost of excluding the cell

phone       data     would    far     outweigh          any       deterrence          benefit      that

exclusion might provide.                      See Dearborn, 327 Wis. 2d 252, ¶35.

This       is   in   part    because           there    is    nothing        concerning          under

current Fourth Amendment doctrine with how the Sheriff's Office

detectives           conducted        themselves.                  Even      if        the    Police

Department's          initial       download          or     retention          gave    cause       for

concern, it's not clear what behavior by the Sheriff's Office

Burch      would     have    this        court    seek       to    deter.9        Based       on    the

arguments presented, Burch has given us no reason to deter law

enforcement          reliance       on    the     computer          records       of     other      law

enforcement          agencies.           In     this       case,    the    societal          cost    of

       Many of Burch's arguments focus on the conduct of the
       9

Police Department and the initial download of his cell phone
data.   He argues that because the Police Department unlawfully
obtained the data, any subsequent accessing of the data violated
the   Fourth  Amendment   because   he  retained  a   reasonable
expectation of privacy in it.     But the conduct of the Police
Department has little bearing on whether we should apply the
exclusionary rule against the Sheriff's Office in this case.
The Police Department's involvement in this case was limited to
an investigation of unrelated crimes and was only fortuitously
useful to the Sheriff's Office's investigation of VanderHeyden's
homicide months later. Exclusion therefore would not serve as a
meaningful deterrent for the Police Department and is not
warranted on that basis.

                                                  14
                                                                    No.    2019AP1404-CR

exclusion would far outweigh the limited benefit——if any——its

application could achieve.

     ¶26       We   conclude    that     suppression    of   Burch's       cell    phone

data is not warranted under the exclusionary rule.                         Regardless

of whether a constitutional violation occurred, there was no

police    misconduct      to    trigger    application       of    the    exclusionary

rule.

                                B.   Fitbit Evidence

     ¶27       Burch also appeals the circuit court's denial of his

motion    to    exclude       evidence    associated     with       Detrie's      Fitbit

device.        Burch   offers    two     arguments.      First,      he    argues     the

Fitbit    evidence     must     be   excluded     because     the    State     did    not

produce expert testimony to establish its reliability.                         Second,

he      maintains      the       Fitbit      evidence        was      insufficiently

authenticated.10         We    review     these   evidentiary       rulings     for   an

erroneous exercise of discretion.                 State v. Nelis, 2007 WI 58,

¶26, 300 Wis. 2d 415, 733 N.W.2d 619.

     10Burch also argues that admission of the Fitbit evidence
violates the Confrontation Clause of the Sixth Amendment to the
United States Constitution.   Burch concedes, however, that his
novel argument "does not neatly fit within the test set forth in
Crawford v. Washington, 541 U.S. 36 (2004)," and that he raised
the issue solely "to preserve for review before higher courts."
Accordingly, we reject Burch's Confrontation Clause claim and do
not address it further.

                                           15
                                                                     No.     2019AP1404-CR

                               1.    Expert Testimony

      ¶28    We    have   held      that     that    "the    requirement         of   expert

testimony is an extraordinary one" and should apply only "when

the issues before the jury are 'unusually complex or esoteric.'"

State   v.   Kandutsch,         2011       WI 78,    ¶28,    336    Wis. 2d 478,           799

N.W.2d 865 (quoting another source).                       Before compelling expert

testimony,        "the    circuit      court        must    first    find        that      the

underlying    issue       is    'not       within   the     realm   of     the    ordinary

experience of mankind.'"               Id. (quoting Cramer v. Theda Clark

Mem'l Hosp., 45 Wis. 2d 147, 150, 172 N.W.2d 427 (1969)).                               What

falls within the "ordinary experience of mankind," meanwhile,

turns on the circuit court's exercise of its discretion "on a

case-by-case basis" to decide whether "the issue is outside the

realm of lay comprehension" or within the "common knowledge" of

"the average juror."           Id., ¶29.

      ¶29    Burch argues that the Fitbit evidence was improperly

admitted because the circuit court should have required expert

testimony to establish the reliability of the science underlying
Fitbit's technology.            He notes that the Fitbit device features

"a   three-axis          accelerometer         sensor        that    generates          data

representing       the    user's       movements,"         but   explains        that      his

"greater concern is with how the device processes the data into

a meaningful output, how that output is exchanged with a phone

or   computer,      and   how       that    evidence       ultimately      ended      up    in

Fitbit's business records."

      ¶30    In its written order rejecting Burch's argument that
expert testimony was required, the circuit court explained that
                                             16
                                                                       No.        2019AP1404-CR

Fitbit's step counters have been in the marketplace since 2009,

and       the     "principle         idea    behind        pedometers . . . for                 a

significantly longer period than that."                        Many smartphones, the

court      added,    "come        equipped   with    a     pedometer         by     default."

Analogizing to a watch and a speedometer, the court noted that

even though the average juror may not know "the exact mechanics"

of    a     technology's           "internal      workings,"         the      public          may

nevertheless        "generally       understand[]        the   principle          of    how    it

functions and accept[] its reliability."                       Similarly, the court

reasoned, a Fitbit's use of sophisticated hardware and software

does not render it an "unusually complex or esoteric" technology

because the average juror is nevertheless familiar with what a

Fitbit does and how it is operated.

      ¶31       This conclusion was reasonable and within the circuit

court's discretionary authority.                    The circuit court correctly

interpreted        the     standard    for     requiring       expert      testimony          and

reasonably applied that standard to the Fitbit evidence before

it.       Given the widespread availability of Fitbits and other
similar         wireless    step-counting         devices      in    today's           consumer

marketplace,        the    circuit     court      reasonably        concluded          Detrie's

Fitbit was not so "unusually complex or esoteric" that the jury

needed     an     expert     to    understand      it.11       The    circuit           court's

       To the extent Burch now argues that the Fitbit is outside
      11

the realm of lay comprehension because it is an "internet of
things" device, we are unpersuaded.      Wireless technology is
nothing new. It is entirely within the "ordinary experience of
mankind" to use a Bluetooth or Wi-Fi connection to transfer data
from one device to another.

                                             17
                                                                         No.       2019AP1404-CR

conclusion that expert testimony was not required under these

circumstances was within the circuit court's discretion.12

                               2.     Authentication

     ¶32     Wisconsin       Stat.    § 909.01          (2019-20)13          sets     out    the

evidentiary standard for authentication:                          "The requirements of

authentication    or     identification            as   a    condition         precedent      to

admissibility are satisfied by evidence sufficient to support a

finding    that   the    matter       in    question         is       what   its     proponent

claims."      Simply put, authentication requires that a circuit

court conclude, within its discretion, that the finder of fact

could     reasonably    determine          that    the       evidence        sought     to    be

admitted is what its proponent says it is.                        Id.; State v. Smith,

2005 WI 104, ¶¶31-33, 283 Wis. 2d 57, 699 N.W.2d 508.                                  In this

case, that means the State's authentication obligation is to

present     sufficient       evidence       to    support         a    finding       that    the

records    produced     by    the    State       are    in    fact       Fitbit's      records

associated with Detrie's Fitbit device.
     ¶33     Notably,    Burch       does    not    actually           disagree      that    the

State's     records     are     accurate          copies       of       Fitbit's       records

associated with Detrie's Fitbit device.                      Instead, he focuses his

challenge    on   whether      the     State       properly           authenticated         "the

     12Of course, opposing counsel may attack the reliability of
admitted evidence.   T.A.T. v. R.E.B., 144 Wis. 2d 638, 652-53,
425 N.W.2d 404 (1988).
     13All subsequent references to the Wisconsin Statutes are
to the 2019-20 version unless otherwise indicated.

                                            18
                                                                  No.    2019AP1404-CR

information within those records."               Specifically, he argues that

"the State failed to show that the Fitbit device reliably and

accurately registered Detrie's steps that evening, and that that

data    was    reliably      and   accurately      transmitted          to   Fitbit's

business records without manipulation."

       ¶34    Burch's argument reaches beyond the threshold question

authentication      presents.       The    circuit      court's     authentication

obligation is simply to determine whether a fact-finder could

reasonably conclude evidence is what its proponent claims it to

be.     Wis. Stat. § 909.01.          The circuit court did so here by

reviewing     the   Fitbit    records      and    the   affidavit       of   "a     duly

authorized     custodian     of    Fitbit's      records"   averring         that    the

records "are true and correct copies of Fitbit's customer data

records," and then concluding the data was self-authenticating

under Wis. Stat. § 909.02(12).14               The circuit court's obligation

is not to scrutinize every line of data within a given record

and decide whether each line is an accurate representation of

the facts.      Rather, once the circuit court concludes the fact-
finder could find that the records are what their proponent

claims them to be, the credibility and weight ascribed to those

       More precisely, the circuit court held that the records
       14

were self-authenticating as certified records of regularly
conducted activity.    See Wis. Stat. § 909.02(12).   Burch has
not, either before the circuit court or this court, challenged
the statements in the affidavit from Fitbit certifying that the
records it provided are accurate copies of its records
associated with Detrie's Fitbit device.

                                          19
                                                                     No.        2019AP1404-CR

records are questions left to the finder of fact.15                               State v.

Roberson,    2019    WI 102,      ¶25,   389    Wis. 2d 190,             935    N.W.2d 813.

The   circuit     court's    conclusion        that    the    Fitbit       records        were

sufficiently authenticated therefore was within its discretion.

                                III.     CONCLUSION

      ¶35   Burch's      appeal    of    his     conviction         for        first-degree

intentional       homicide    challenged       the    denial        of    two     pre-trial

evidentiary orders.          We uphold both orders, and therefore affirm

the   judgment      of   conviction.           Burch's       cell    phone        data    was

properly admitted because, even if there was some constitutional

defect in how it was obtained or retained, exclusion would be an

improper remedy.         The circuit court also permissibly exercised

its discretion in admitting the Fitbit evidence; no expert was

required and the State sufficiently authenticated the records

from Fitbit.

      By    the    Court.——The      judgment      of     the    circuit           court    is

affirmed.

       Here, too, opposing counsel can attack the reliability of
      15

admitted evidence. See T.A.T., 144 Wis. 2d at 652-53.

                                         20
                                                            No.   2019AP1404-CR.rgb

      ¶36    REBECCA GRASSL BRADLEY, J.         (concurring).         I join the

majority opinion in full.           Because there are no controlling

cases interpreting the Fourth Amendment to prohibit the second

search of Burch's cellphone by the Brown County Sheriff's Office

(Sheriff's Office), the exclusionary rule does not apply and

suppression of the evidence obtained from that search would be

improper.1     I write separately to discuss the application of the

Fourth Amendment to warrantless second searches of smartphones

without consent.

      ¶37    Under the original meaning of the Fourth Amendment,

law enforcement generally will need a warrant to search the

contents of a smartphone, absent an exception to the warrant

requirement.      The consent-to-search exception, which the State

argues authorized law enforcement to conduct a second search of

Burch's smartphone data, does not extend to a second search of a

smartphone by a different law enforcement agency investigating

an entirely separate crime.          "Modern cell phones are not just

another technological convenience.             With all they contain and
all they may reveal, they hold for many Americans 'the privacies

of   life.'"      Riley   v.   California,     573   U.S.     373,    403    (2014)

(quoting Boyd v. United States, 116 U.S. 616, 630 (1886)).                       The

Fourth      Amendment   secures    "'the     privacies      of    life'     against

'arbitrary     power,'"    and    embodies    the    "central        aim    of   the

Framers . . . 'to place obstacles in the way of a too permeating

      1I also agree with the majority that the circuit court did
not erroneously exercise its discretion by admitting evidence
from Douglass Detrie's Fitbit device.

                                      1
                                                                 No.    2019AP1404-CR.rgb

police surveillance.'"             Carpenter v. United States, 138 S. Ct.

2206, 2214 (2018) (quoted sources omitted).

       ¶38     The contents of smartphones constitute "papers" and

"effects" secured by the Fourth Amendment, giving each of those

categories their historical meanings and bearing in mind that "a

cell phone search would typically expose to the government far

more than the most exhaustive search of a house."                           Riley, 573

U.S. at 396.          Accordingly, law enforcement generally must get a

warrant before searching a cell phone.                     Id. at 403.           Because

Burch's consent to search covered only                     the Green Bay Police

Department's          initial    search    of    his    smartphone       for    evidence

related to a hit-and-run investigation, a warrant should have

been       procured    before     the   Sheriff's       Office    searched       Burch's

smartphone data as part of an unrelated murder investigation.

Because neither this court nor the United States Supreme Court

has decided this novel issue, the Sheriff's Office committed no

misconduct in searching Burch's cell phone and the circuit court

properly       admitted     the    evidence       obtained       from     the   search.
Accordingly, I respectfully concur.

                                             I

       ¶39     In June 2016, a few weeks after Nicole VanderHeyden's

murder and the ensuing investigation by the Sheriff's Office,

the    Green     Bay     Police    Department      (Police       Department)       began

investigating an entirely unrelated crime:                       an auto theft that

resulted in a hit-and-run incident.2                   The stolen car belonged to

Burch's      roommate,     and    law     enforcement     identified       Burch   as   a

       2   The vehicle was also lit on fire.

                                             2
                                                                   No.   2019AP1404-CR.rgb

person of interest because he had last driven the car.                           Officer

Robert   Bourdelais          of   the    Police    Department       interviewed    Burch

about    the    hit    and     run.       Burch    denied    any    involvement,      but

informed Officer Bourdelais that, on the night of the hit and

run, he was texting a woman who lived one block away from the

location of the accident.                 Burch stated that he did not go to

the woman's house on the night of the incident, and never made

arrangements      to      go      to    her    house.       According       to   Officer

Bourdelais' testimony, he and Burch had the following exchange:

    I asked him if I could see the text messages between
    him and [the woman], if my lieutenant and I could take
    a look at his text messages.         He said that we
    could . . . .    I [then] asked him if he would be
    willing to let me take his phone to this detective,
    download the information off the phone and then I'd
    bring the phone right back to him, probably take a
    half an hour and he said that would be fine.
    ¶40        The attorney eliciting Officer Bourdelais' testimony

inquired:         "When      you       asked   [Burch]      about    downloading      the

information off of his phone, did you specifically limit the

information to the text messages when you were talking to him?"

Officer Bourdelais responded:

    No, I didn't.    Initially, when I had asked him, hey,
    do you mind if we take a look at those text messages,
    I refer to them as text messages because he said he
    was texting [the woman] back and forth, but from my
    experience   as   a  police   officer  I  know   people
    communicate [by] phone calls, text messages, texting
    apps like WhatsApp, MINE, Facebook Messenger, things
    like that.      So that's the information, I wanted
    information to corroborate that whatever conversation
    he had with [the woman] or communication he had
    supported his claims that he never went over to her
    house or made arrangements to go over to her house.

                                               3
                                                                No.   2019AP1404-CR.rgb

       ¶41     Following    the    exchange      between    Burch       and      Officer

Bourdelais, Burch signed a consent form which read as follows:

"I, George Stephen Burch, . . . voluntarily give Det. Danielski,

Officer      Bourdelais,    or    any   assisting     personnel       permission        to

search       my . . . Samsung      cellphone."          Subsequently,           at     the

instruction of Officer Bourdelais, a Police Department forensic

examiner downloaded all of the data from Burch's cellphone into

the Police Department records database.                   The forensic examiner

then converted the data into a readable format, and tabbed the

data into categories such as text messages, images, and internet

history.       At the homicide trial, the forensic examiner testified

that    the     Police   Department      retains      smartphone        data     for   an

indefinite amount of time, noting that "[e]ver since [she] [has]

been employed with [the Police Department], [they] have saved

all extractions for long-term storage for as far back as [she]

[has] been employed," which was roughly two years at the time of

trial.

       ¶42     In August 2016 (two months after Burch consented to
the search of his phone for the hit-and-run investigation), the

Sheriff's Office identified Burch as a person of interest in the

investigation into the murder of VanderHeyden based upon a DNA

match    on    VanderHeyden's      socks.       Relying    on    databases        shared

between        the   Sheriff's     Office       and   other       local        entities,

detectives from the Sheriff's Office discovered that the Police

Department had prior contact with Burch while investigating the

unrelated hit-and-run incident.                 After the detectives learned
that     the    Police     Department     had    extracted        all     of     Burch's

                                          4
                                                                     No.     2019AP1404-CR.rgb

smartphone data in June 2016, they procured a copy of the data

from       the    Police    Department        and    searched     its        contents    "for

anything in the timeframe of the night of [the murder] into the

[following]         morning,       whether     it     be     calls,     texts,       internet

history, any kind of location data available from that device."

The detectives did not obtain a warrant for this search.                                   In

reviewing         the    data,     the    detectives       discovered        that,    shortly

after the murder, Burch repeatedly searched for news articles

about the murder using his internet browser.

       ¶43       Additionally, during their warrantless search of the

smartphone's contents, the detectives learned that Burch had a

Google email account (Gmail).                      The detectives were aware that

Gmail addresses are associated with a Google Dashboard, which

tracks      an    individual's           location    based    upon     GPS,     Wi-Fi,    and

cellphone tower data.               The detectives procured a search warrant

to     obtain      Google        Dashboard    information       from       Google.        The

location         data    placed     Burch's    smartphone       at     various       critical

places on the night of the murder, including the location of
VanderHeyden's body and the on-ramp where her discarded clothing

was discovered.

       ¶44       Burch     was    arrested     and     charged        with     first-degree

intentional homicide.                In a pre-trial motion, Burch moved to

suppress the evidence obtained by the Sheriff's Office from the

warrantless search of his smartphone data.3                           Burch argued that

the Sheriff's Office "violated the Fourth Amendment when [it]

       Burch also filed a motion to exclude evidence related to
       3

Detrie's Fitbit device, which the circuit court denied.

                                               5
                                                            No.    2019AP1404-CR.rgb

searched    the     phone    data   initially      seized     by        [the    Police

Department]."       Specifically, Burch contended that the Sheriff's

Office "blew past Mr. Burch's scope of consent, and likewise,

obliterated   any     Fourth    Amendment      warrant    exceptions."             The

circuit court denied Burch's suppression motion, and the State

introduced at trial the evidence obtained from the smartphone.

The jury convicted Burch of first-degree intentional homicide.

Burch    appealed    the     circuit     court's   decision        to     admit    the

evidence procured by the Sheriff's Office from its search of his

smartphone data.       The court of appeals certified Burch's Fourth

Amendment     challenge        to      this    court,     and       we         accepted

certification.

                                         II

    ¶45     The Fourth Amendment provides:

    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.
U.S. Const. amend. IV.          "The first clause outlaws promiscuous

search and seizure, even as the second clarifies precisely what

will be required for a particularized warrant to be valid."

Laura K. Donohue, The Original Fourth Amendment, 83 U. Chi. L.

Rev. 1181, 1193 (2016); State v. Pinder, 2018 WI 106, ¶¶48-51,

384 Wis. 2d 416, 919 N.W.2d 568.              As understood at the time the

Fourth   Amendment     was    ratified,       "[t]he    government        could    not

violate the right against search and seizure of one's person,
house, papers, or effects absent either a felony arrest or a
                                         6
                                                                           No.     2019AP1404-CR.rgb

warrant meeting the requirements detailed in the second clause."

Donohue, supra, at 1193.

       ¶46       As    the    United       States       Supreme       Court      has   repeatedly

held,       "the      ultimate       touchstone         of     the    Fourth        Amendment     is

'reasonableness.'"               Brigham City v. Stuart, 547 U.S. 398, 403

(2006).          "[W]hether an individual has a reasonable expectation

of      privacy         in      avoiding        the          method        of        search      and

a reasonable expectation of privacy in the place searched are

the     questions            that    drive     a        court's       examination          of    the

reasonableness of the search."                         State v. Brereton, 2013 WI 17,

¶32, 345 Wis. 2d 563, 826 N.W.2d 369.                          "The general rule is that

searches         and    seizures         conducted       without       a     warrant       are   not

reasonable."                 State    v.     Randall,          2019     WI       80,    ¶10,     387

Wis. 2d 744, 930 N.W.2d 223.                       However, there are a number of

exceptions to the warrant requirement.                            See Riley, 573 U.S. at

382 ("In the absence of a warrant, a search is reasonable only

if     it    falls      within       a     specific          exception        to     the   warrant

requirement.").              "One of the exceptions to the warrant rule is
that        an     individual's            consent        to     search          satisfies       the

constitutional           'reasonableness'               requirement."               Randall,     387

Wis. 2d 744, ¶10; see also Birchfield v. North Dakota, 136 S.

Ct. 2160, 2185 (2016) ("It is well established that a search is

reasonable when the subject consents[.]").                                   "If a search is

premised on an individual's consent, it must cease immediately

upon revocation of that consent," and an individual "may of

course delimit as she chooses the scope of the search to which

                                                   7
                                                         No.   2019AP1404-CR.rgb

she     consents."       Randall,        387   Wis. 2d 744,    ¶10    (internal

alterations and citations omitted).

      ¶47   Just a few years ago, the United States Supreme Court

addressed     the     Fourth     Amendment's    application    to     a    modern

phenomenon:     the proliferation of smartphones and their ever-

increasing capacity to store mass amounts of data.                   The Court

held that law enforcement generally must obtain a warrant before

conducting a search of smartphone data.             Specifically, the Riley

Court     clarified    that     "[its]    holding . . . is     not    that     the

information on a cell phone is immune from search," but "instead

that a warrant is generally required before such a search, even

when a cell phone is seized incident to arrest."4                    Riley, 573

U.S. at 401.        In reaching this holding, the Court recognized the

"pervasiveness that characterizes cell phones" and how "[c]ell

phones differ in both a quantitative and a qualitative sense

from other objects."           Id. at 393, 395.     "The possible intrusion

on privacy is not physically limited in the same way [as other

objects] when it comes to cell phones."                  Id. at 394.           "An
internet search and browsing history, for example, can be found

on an internet-enabled phone and could reveal an individual's

private     interests      or     concerns,"      and   "historic         location

      4Although Riley involved the search-incident-to-arrest
exception to the Fourth Amendment warrant requirement, the
principles it espouses apply more broadly.        See Riley v.
California, 573 U.S. 373, 386 (2014) ("[O]fficers must generally
secure a warrant before conducting such a search [of a cell
phone]."); see also People v. Hughes, 958 N.W.2d 98, 108 (Mich.
2020) ("In Riley v. California, the Supreme Court of the United
States held that officers must generally obtain a warrant before
conducting a search of cell-phone data.").

                                          8
                                                               No.      2019AP1404-CR.rgb

information"      could     allow     law       enforcement        to     "reconstruct

someone's specific movements down to the minute."                          Id. at 395-

96.

      ¶48    The United States Supreme Court fully understood that

its   decision    "[would]     have   an       impact   on   the     ability      of   law

enforcement to combat crime."              Id. at 401.         After all, "[c]ell

phones have become important tools in facilitating coordination

and communication" for individuals committing crimes and "can

provide     valuable      incriminating          information       about        dangerous

criminals."      Id.   But "[p]rivacy comes at a cost."                   Id.    And the

Fourth Amendment is designed to safeguard the people's security

against     unreasonable      government        intrusion.         Riley      recognizes

that the Fourth Amendment safeguards this right by generally

requiring law enforcement to procure a warrant before searching

a smartphone.

      ¶49    A warrant requirement for searches of smartphone data

comports with the original meaning of the Fourth Amendment.                            The

Framers, "after consulting the lessons of history, designed our
Constitution to place obstacles in the way of a too permeating

police surveillance, which they seemed to think was a greater

danger to a free people than the escape of some criminals from

punishment."      United States v. Di Re, 332 U.S. 581, 595 (1948).

In    particular,      "the     Fourth         Amendment     was        the      founding

generation's     response      to   the    reviled      'general        warrants'      and

'writs of assistance' of the colonial era, which allowed British

officers to rummage through homes in an unrestrained search for
evidence of criminal activity.                 Opposition to such searches was

                                           9
                                                                      No.   2019AP1404-CR.rgb

in fact one of the driving forces behind the Revolution itself."

Riley, 573 U.S. at 403.                  "Indeed, the character of that threat

implicates the central concern underlying the Fourth Amendment——

the concern about giving police officers unbridled discretion to

rummage at will among a person's private effects."                                 Arizona v.

Gant,   556       U.S.    332,     345    (2009).        For    the     Framers,      it   was

absolutely necessary to ensure "the government not be allowed

free    rein       to     search     for        potential      evidence       of     criminal

wrongdoing."           Donohue, supra, at 1194.

       ¶50     The Framers designed the Fourth Amendment to protect

the people from government overreach.                        Described as the "very

essence      of    constitutional          liberty     and     security,"      the     Fourth

Amendment         applies    to     "all        invasions      on   the      part    of    the

government and its employes of the sanctity of a man's home and

the privacies of life."              Boyd, 116 U.S. at 630.                 "It is not the

breaking of [one's] doors, and the rummaging of his drawers,

that constitutes the . . . offense; but it is the invasion of

his infeasible right of personal security, personal liberty, and
private property[.]"               Id.      With this understanding in mind,

"[t]he Supreme Court has . . . confirmed that the basic purpose

of   the     Fourth       Amendment       'is     to   safeguard       the    privacy      and

security       of        individuals       against        arbitrary          invasions      by

governmental officials'"——that is, "to secure 'the privacies of

life' against 'arbitrary power.'"                        Matthew DeVoy Jones, Cell

Phones are Orwell's Telescreen: The Need for Fourth Amendment

Protection        in     Real-Time       Cell    Phone    Location      Information,        67

                                                10
                                                                       No.      2019AP1404-CR.rgb

Clev. St. L. Rev. 523, 533 (2019) (quoting Carpenter, 138 S. Ct.

at 2213-14).

       ¶51    The Fourth Amendment specifically recognizes the right

of people to be secure in their "persons, houses, papers, and

effects."       U.S. Const. amend. IV; see United States v. Jones,

565 U.S. 400, 406 (2012) ("[F]or most of our history the Fourth

Amendment      was    understood        to    embody      a     particular           concern     for

government trespass upon the areas ('persons, house, papers, and

effects') it enumerates.").                  Much modern analysis of the Fourth

Amendment has centered upon the primacy of protecting "houses."

See Payton v. New York, 445 U.S. 573, 589 (1980) ("The Fourth

Amendment      protects      the    individual's          privacy          in    a     variety    of

settings.      In none is the zone of privacy more clearly defined

than when bounded by the unambiguous physical dimensions of an

individual's home[.]").                However, as the Riley Court explained,

smartphones         implicate      privacy     interests            more    compelling          than

even those associated with the home.                      "A cell phone search would

typically      expose       to   the    government            far    more       than    the     most
exhaustive search of a house:                      A phone not only contains in

digital      form    many    sensitive        records         previously         found     in    the

home; it also contains a broad array of private information

never found in a home in any form[.]"                          Riley, 573 U.S. at 396-

97.

       ¶52    Given the nature of its contents, a smartphone is not

just   another       personal      item;     it    is     a    device       that       holds    many

modern    "privacies        of   life"——an         area       that    receives          acute    and
particularized protection from government interference under the

                                              11
                                                                   No.    2019AP1404-CR.rgb

Fourth Amendment.        See Boyd, 116 U.S. at 630.                            Governmental

searches     of    smartphones      invade      "the       indefeasible             right   of

personal   security,     personal         liberty,        and    private         property,"

which Americans hold "sacred."              Id.      Permitting law enforcement

to rummage through the data residing in smartphones without a

warrant    would     "allow[]      free    rein      to     search        for       potential

evidence   of     criminal   wrongdoing,"         which      the    Fourth          Amendment

prohibits.        With respect to smartphone data, as in the home,

"all details are intimate details, because the entire area is

held safe from prying government eyes."                         See Kyllo v. United

States, 533 U.S. 27, 37 (2001).

    ¶53    The      Fourth   Amendment         includes         both          "papers"      and

"effects" among the four enumerated categories protected from

unreasonable searches.           The contents of smartphones constitute

"papers"     within    the     original        understanding             of     the    Fourth

Amendment.        "Historically, private papers, including documents

and pamphlets that challenged governmental power, served as a

central point of contestation in the Founding era."                                    Andrew
Guthrie Ferguson, The "Smart" Fourth Amendment, 102 Cornell L.

Rev. 547, 595-96 (2017).            The Fourth Amendment's protection of

"papers"   "reflect[s]       the    importance         of    freedom           of     thought,

expression, and communication."                Id.        According to Lord Camden

in his seminal decision in Entick v. Carrington, "papers are

often the dearest property a man can have."                          19 How. St. Tr.

1029 (C.P. 1765).

    ¶54    The      Framers'       inclusion         of     "papers"           within       the
protections of the Fourth Amendment was motivated in part by the

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case    of    John   Wilkes,       "who    was    targeted         for        writing   mocking

articles about King George III" and had his papers seized by

investigating        officers.           Ferguson,        supra,         at    596     (citation

omitted).         "The Wilkes controversy . . . directly influenced the

[F]ramers      of    the   Fourth     Amendment.             The    English          search     and

seizure cases received extensive publicity in England and in

America,      and    the    Wilkes       case     was     the      subject       of     as     much

notoriety and comment in the colonies as it was in Britain."

Eric Schnapper, Unreasonable Searches and Seizures of Papers, 71

Va. L. Rev. 869, 912-13 (1985).                    "Wilkes' cause generated many

supporters among American colonists, some of whom became key

figures in the framing of the Constitution."                         Id. at 913.              Based

upon Wilkes' case, "[p]rotecting private papers . . . became a

central rallying cry in the creation of constitutional liberty,"

receiving         explicit        protection        under          the        United         States

Constitution.        Ferguson, supra, at 596.

       ¶55    Today, the people's "papers" largely exist in digital

form.        "E-mails, texts, and other social media communication
have    replaced      letter      writing."         Id.      at    599.         Additionally,

calendars,        notes,   health     information,            photographs,            restaurant

and hotel reservations, airline flights, shopping and browsing

histories, as well as banking transactions all reside in (or are

accessible from) smartphones, forming a digital diary of one's

life, accessible from a single source.                            Given the breadth and

detail of this information, "individuals have expectations of

privacy      in    their   digital        papers."           Id.   at     600.         From     the
Framers'      outrage      over    the     search       of    Wilkes'          papers    to    the

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                                                                        No.   2019AP1404-CR.rgb

Court's       concern        regarding         the     search          of     David      Riley's

smartphone, the overarching aim "has always been the protection

of ideas embodied in those papers"——not whether the papers are

in physical or digital form.               Id. at 613.

       ¶56     Some portion of the contents of smartphones, as well

as    the    devices       themselves,     also       constitute            "effects,"     which

"have historically been understood to mean personal property——

the    objects       we    possess."       Id.       at     578    (citing         Dictionarium

Brittanicum (Nathan Baily ed., 1730) (defining "effects" as "the

goods of a merchant, tradesman") and Noah Webster, First Edition

of     an    American       Dictionary      of       the    English         Language       (1828)

(defining "effects" as "goods; moveables; personal estate")).

"The        early     American       understanding               distinguished         personal

property       from       real    property,"        and    "personal          property     meant

physical belongings"——items which were "obviously prized by the

Founders" and accordingly received Fourth Amendment protection.

Id.         Founding-era         history    "demonstrates              that    effects      were

specifically         included      in    the    constitutional              text    [not   only]
because       of    the    harms    to   privacy       and       dignity      that    could    be

incurred in their inspection, but also because of the risk of

mishandling or damage generally associated with interferences

with personal property."                 Maureen E. Brady, The Lost "Effects"

of     the    Fourth        Amendment:           Giving          Personal      Property       Due

Protection, 125 Yale L.J. 946, 987 (2016).                             Founding-era sources

suggest the Framers understood "[p]ersonal property [to] give[]

its owner a right to exclude others from possessing, using, and
interfering         with    the    effect"——and           most    of    all    to    "protect[]

                                               14
                                                                    No.    2019AP1404-CR.rgb

privacy interests with respect to the property."                               Id. at 993-94

(discussing founding-era sources, including William Blackstone's

Commentaries         and     Lord     Camden's          judgment          in     Entick      v.

Carrington).

      ¶57     Although "'effects' has captured rather less of the

[United     States]    Supreme       Court's       attention"       than       "papers"     and

"houses,"     when    the    Court     has    addressed       the    topic,          "property

considerations        loom    large."         Laura      K.    Donohue,          The    Fourth

Amendment in a Digital World, 71 N.Y.U. Ann. Surv. Am. L. 553,

679 (2017).       For example, in United States v. Jones, the United

States Supreme Court held that law enforcement's installation of

a GPS device on an individual's vehicle to monitor the vehicle's

movements     constituted       a    "search"       under     the   Fourth        Amendment,

deeming it "beyond dispute" that a vehicle is an "effect" within

the meaning of the Fourth Amendment.                    565 U.S. 400, 404 (2012).

The Court emphasized the government's "physical intrusion" of

the "effect" at issue.              Id. at 411.         The Court did not focus on

the physical attachment of the GPS device to the effect but
rather      the      device's       capture        of    sensitive             and     private

information, "relay[ing] more than 2,000 pages of data over [a]

4-week period."            Id. at 403; see also Ferguson, supra, at 606

("[In Jones] the real harm was exposing the revealing personal

data about the effect (car).").                    That is, in Jones the Fourth

Amendment analysis turned on the "capturing of data trails" of

the   owner    and    "invad[ing]       the       informational       security         of   the

effect."      Ferguson, supra, at 606.                   The Court's reasoning in
Jones applies no less to smartphones and the data they hold,

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                                                                     No.    2019AP1404-CR.rgb

supporting      the      characterization            of    smartphones          as    "effects"

entitled to constitutional protection from unreasonable searches

and seizures.

                                               III

       ¶58    Having         established        a     historical       basis          for     the

application       of    the     Fourth      Amendment's      warrant        requirement        to

smartphones       and    their       data,    it     is    necessary       to    address      the

application of the consent exception to the warrant requirement

within the context of the facts of Burch's case.                                 It is well-

established that "[o]ne of the exceptions to the warrant rule is

that     an     individual's           consent        to     search         satisfies         the

constitutional          'reasonableness'            requirement."               Randall,      387

Wis. 2d 744,       ¶10;       see    also     Birchfield,      136     S.       Ct.   at    2185.

Burch gave consent for the Police Department to download and

search his smartphone and its data as part of the investigation

of the hit-and-run incident in June 2016.                              According to his

testimony, Officer Bourdelais asked Burch if "[he] could see the

text messages between him and [the woman]" on the night of the
hit-and-run incident.               Officer Bourdelais then asked Burch if he

could     "take        his     phone     to     this       detective,           download      the

information       off    the    phone"       and    then    bring    it     right      back   to

Burch.       Burch agreed to all requests in this exchange and signed

a consent form saying he "voluntarily give[s] Det. Danielski,

Officer      Bourdelais,        or   any     assisting      personnel        permission        to

search [his] . . . Samsung cellphone."                       Burch permitted Officer

Bourdelais       "or      any       assisting        personnel"      to         download      his
smartphone's data and search for evidence of the hit-and-run

                                               16
                                                                         No.    2019AP1404-CR.rgb

incident.          Burch's consent encompassed the Police Department's

investigation of a particular crime.                          The Constitution permitted

this    search.           Schneckloth       v.     Bustamonte,          412     U.S.    218,    222

(1973) ("[A] search conducted pursuant to a valid consent is

constitutionally permissible.").

       ¶59    Two months later, a different law enforcement agency——

the    Sheriff's         Office——searched          Burch's        smartphone          data   while

investigating         an     entirely       separate          crime.      This    search       went

beyond       the     scope      of    Burch's          consent.         Officer        Bourdelais

questioned Burch in June 2016 regarding the hit-and-run incident

only,     and       obtained          Burch's      consent        to      download        Burch's

smartphone         data    "[to]      corroborate         that     whatever       conversation

[Burch] had with [the woman] . . . supported his claims that he

never went over to her house" the night of the hit and run.                                    The

consent form did not include any language authorizing a second

search by a separate law enforcement agency                                   for a different

crime.         The       form    authorized            only    Officer        Bourdelais,      the

forensic        examiner         (Det.      Danielski),           and      their        assisting
personnel to view the smartphone's contents.                              Any search beyond

the scope of Burch's consent would require a warrant.

       ¶60    The State argues that this court's decision in State

v. Betterley, 191 Wis. 2d 406, 529 N.W.2d 216 (1995), allows law

enforcement to take a "second look" at smartphone data that was

previously searched.                 That case does not apply to searches of

cell phone data.             In Betterley, officers at the St. Croix County

Jail    seized       a    ring       from   the    defendant           during    an     inventory
search.       Id. at 414.              Later that day, a New Richmond police

                                                  17
                                                                      No.     2019AP1404-CR.rgb

officer asked to see the ring, believing it was evidence that

the defendant had committed insurance fraud.                            Id. at 415.           The

New    Richmond         police      officer     retained        the     ring    as     evidence

without obtaining a warrant.                      Id.      This court held that "the

permissible extent of the second look [at evidence] is defined

by what the police could have lawfully done without violating

the defendant's reasonable expectations of privacy during the

first search, even if they did not do it at that time."                                  Id. at

418.        Because the           defendant had a diminished expectation in

privacy in the ring after forfeiting it during the first search,

the second look at the ring was permissible, so long as it was

"no more intrusive" than the first search.                        Id.

       ¶61     Betterley does not apply to cell phone data retrieved

pursuant       to       the    owner's      consent.            Betterley       involved       an

inventory search of an item, not the consent-to-search exception

to    the    warrant       requirement.           Unlike      searches        conducted    with

consent, inventory searches are "administrative by nature, not

an investigation motivated by a search for evidence."                                 State v.
Weber,      163     Wis. 2d 116,         132,     471      N.W.2d 187       (1991).        More

importantly,        physical        items     such      as    rings     are    qualitatively

different than searches of smartphone data.                              Examination of a

ring reveals nothing more than the physically observable item

itself, while smartphones contain——and conceal——the "privacies

of    life,"      which       generally     are      not     viewable    by     others    at   a

glance.           For    this      reason,      smartphones        "differ       in    both     a

quantitative         and      a    qualitative          sense    from    other        objects."
Riley, 573 U.S. at 393.                  "[I]t is no exaggeration to say that

                                                18
                                                                   No.   2019AP1404-CR.rgb

many of the more than 90% of American adults who own a cell

phone keep on their person a digital record of nearly every

aspect      of    their     lives——from          the    mundane    to    the    intimate.

Allowing the police to scrutinize such records on a routine

basis is quite different from allowing them to search a personal

item or two in the occasional case."                        Id. at 395.         Certainly,

"the possible intrusion on privacy is not physically limited in

the same way [as other objects] when it comes to cell phones."

Id. at 394.         Accordingly, Betterley does not inform the Fourth

Amendment analysis governing searches of cell phone data.

      ¶62    Even if "a Fourth Amendment violation has occurred,"

however,     it    "does        not    mean     the    exclusionary      rule   applies,"

particularly        because       "exclusion          [of   evidence]     is    the     last

resort."         State v. Dearborn, 2010 WI 84, ¶35, 327 Wis. 2d 252,

786   N.W.2d 97.            "To       trigger    the    exclusionary      rule,        police

misconduct must be sufficiently deliberate that exclusion can

meaningfully        deter       it,    and    sufficiently        culpable      that    such

deterrence is worth the price paid by the justice system."                              Id.,
¶36 (quoted source omitted).                     For the reasons stated in the

majority     opinion,       there       was     no    misconduct    by   the    Sheriff's

Office.      Neither this court nor the United States Supreme Court

has declared that second searches of cell phone data by separate

law   enforcement         agencies        require       a   warrant.       Accordingly,

suppression        of     the     evidence       obtained     during     the    Sheriff's

Office's second search would be inappropriate and I respectfully

concur.

                                                19
                                                          No.   2019AP1404-CR.rgb

                                   * * *

       ¶63   "The great end, for which men entered into society,

was to secure their property."              Entick v. Carrington, 19 How.

St. Tr. 1029 (C.P. 1765) (Lord Camden presiding).                     "Property

must   be    secured,   or   liberty   cannot    exist."        Discourses    on

Davila, in 6 The Works of John Adams 280 (C. Adams ed. 1851).

"The    Fourth   Amendment    imposes       limits   on   search-and-seizure

powers in order to prevent arbitrary and oppressive interference

by enforcement officials with the privacy and personal security

of individuals."        United States v. Martinez-Fuerte, 428 U.S.

543, 554 (1976).        Because smartphones contain the "privacies of

life," law enforcement generally needs a warrant to search the

data they hold unless an exception to the warrant requirement

applies.

                                       20
                                                                          No.   2019AP1404-CR.rfd

      ¶64      REBECCA          FRANK       DALLET,     J.        (concurring          in     part,

dissenting         in    part).         Under    the    Fourth          Amendment,     when     the

police    want      to     search       a    person's     private         information,        they

generally need a warrant.                      The Brown County Sheriff's Office

searched George Steven Burch's private cell phone data without

obtaining a warrant, assuming that Burch's consent for another

agency    to       download       his       phone's    data       for    a   wholly     separate

investigation obviated its Fourth Amendment duty to do so.                                       It

did not.       The Sheriff's Office's warrantless search of Burch's

cell phone data violated the Fourth Amendment, and the evidence

obtained from that unlawful search should be suppressed.                                        The

majority       opinion's           contrary           holding       ignores        the        novel

constitutional            problems          presented        by     private        cell       phone

information, is inconsistent with the Fourth Amendment's text,

and   undermines          the     exclusionary         remedy      for       Fourth    Amendment

violations.         I therefore respectfully dissent from that part of

the majority opinion.1

                                        I.    BACKGROUND
      ¶65      A        Green     Bay       Police      Department            (GBPD)        officer

interviewed Burch while investigating crimes involving the car

Burch would borrow for work.                     Burch denied his involvement but

acknowledged that he was text messaging a friend that night who

lived near the scene.                   When the officer asked Burch if he and

his lieutenant could see those text messages, Burch verbally

consented.          After the officer explained that it was easier to

      1I join Parts I. and II.B. of the majority opinion because
I agree that the circuit court permissibly admitted evidence
regarding a Fitbit device.

                                                 1
                                                              No.    2019AP1404-CR.rfd

download      "the     information"    from      the      phone     than   to    take

screenshots, Burch verbally consented to allowing the officer to

take his phone to a GBPD detective for that purpose.2                             The

officer then presented Burch with a standardized written consent

form.      The form contained the heading "City of Green Bay Police

Department" and indicated that Burch "voluntarily" gave a named

GBPD officer, a named GBPD detective, as well as any "assisting

personnel,"        "permission   to   search"       his    "Samsung     Cellphone."

Burch signed the form.           The officer testified that he requested

only       "text     messages,    phone       calls,      Facebook     posts,     and

photographs taken any time after 11:00 p.m." the night of the

accident; yet, to access that information, the GBPD downloaded

the entire contents of Burch's phone.

       ¶66    Two     months     later,       the      Sheriff's       Office     was

investigating a homicide that had occurred a few weeks before

the crimes being investigated by the GBPD.                   It matched Burch's

DNA to DNA collected from the victim's body, her socks, and a

cord believed to be used in her murder.                    The Sheriff's Office

       At trial, the officer testified that by "the information,"
       2

he meant any communications between Burch and his friend that
would corroborate Burch's alibi:

       Initially, when I had asked [Burch], hey, do you mind
       if we take a look at those text messages, I refer to
       them as text messages because he said he was texting
       [his friend] back and forth, but from my experience as
       a police officer I know people communicate phone
       calls, text messages, texting apps like WhatsApp,
       MINE, Facebook Messenger, things like that. So that's
       the information, I wanted information to corroborate
       that whatever conversation he had with [his friend] or
       communication he had supported his claims that he
       never went over to [the victim's] house or made
       arrangements to go over to her house.

                                          2
                                                              No.     2019AP1404-CR.rfd

also    discovered       that   the    GBPD    had    retained      the     full    data

extraction from Burch's cell phone.                  After reviewing the GBPD's

files    and    seeing    Burch's     signed   consent      form,     the    Sheriff's

Office searched that data without first obtaining a warrant.

The search led the Sheriff's Office to Burch's internet search

history and his Google email account.                       The internet history

revealed that Burch had viewed online stories about the victim's

disappearance 64 times.           The email account allowed the Sheriff's

Office to issue Google a subpoena for Burch's Google Dashboard

records, which included his location data from the night of the

murder.        The location data placed Burch's cell phone near the

victim's residence and the field where her body was discovered

around the time of the victim's death.

                                     II.   ANALYSIS

       ¶67     The Fourth Amendment inquiry here is two-fold.                         The

first     consideration         is     whether       the     Sheriff's        Office's

warrantless search of the GBPD's download of Burch's data was

unreasonable.       If so, it violated the Fourth Amendment, and the
question       becomes    whether      excluding      the    unlawfully       obtained

evidence would sufficiently deter the same police conduct in the

future.        These questions involve a mixed standard of review,

under which we uphold the circuit court's findings of historical

fact unless they are clearly erroneous, but we review de novo

the    application       of   constitutional     principles      to    those       facts.

See State v. Blackman, 2017 WI 77, ¶25, 377 Wis. 2d 339, 898
N.W.2d 774.

                                           3
                                                                     No.    2019AP1404-CR.rfd

 A.    The Sheriff's Office's Warrantless Search Was Unreasonable.

       ¶68     The Fourth Amendment to the United States Constitution

prohibits the government from conducting "unreasonable" searches

of a person, a person's home, or her "effects":

       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 . . . .
The Amendment seeks to secure "the privacies of life" against

such unreasonable searches by placing "obstacles in the way of a

too permeating police surveillance."                         See Carpenter v. United

States,      585        U.S. ___,       138    S. Ct. 2206,       2214   (2018).         Police

surveillance amounts to a "search," for purposes of the Fourth

Amendment, when it collects information in which the person has

a reasonable expectation of privacy.                      E.g., id. at 2213-14.

       ¶69     To protect one's reasonable expectation of privacy,

the     text       of        the     Fourth    Amendment     communicates         a     "strong

preference for searches conducted pursuant to a warrant."                                      See

Illinois          v.        Gates,    462     U.S. 213,    236    (1983);      U.S.      Const.

amnd. IV.          Indeed, a warrantless search is per se unreasonable,
see Schneckloth v. Bustamonte, 412 U.S. 218, 219 (1973), and

presumptively               violates     the    Fourth     Amendment,      see        State    v.

Tate, 2014 WI 89, ¶27, 357 Wis. 2d 172, 849 N.W.2d 798.                                       That

presumption is overcome only when the warrantless search falls

under       one        of     the    "few     specifically       established      and     well-

delineated exceptions."                     State v. Coffee, 2020 WI 53, ¶24, 391

Wis. 2d 831, 943 N.W.2d 845.
       ¶70     Consent is one such exception.                      State v. Hogan, 2015

WI    76,    ¶55,           364    Wis. 2d 167,    868    N.W.2d 124.        As       with     any

                                                  4
                                                                     No.    2019AP1404-CR.rfd

exception to the warrant requirement, consent is "jealously and

carefully drawn," and must be "confined in scope" and "strictly

circumscribed."          See Jones v. United States, 357 U.S. 493, 499

(1958); Terry v. Ohio, 392 U.S. 1, 25-26, 29 (1968).                            Consent to

a    particular      search        must    therefore          be     "unequivocal        and

specific."        State v. Reed, 2018 WI 109, ¶8, 384 Wis. 2d 469, 920

N.W.2d 56.        Even absent express limits, the scope of consent is

neither "boundless" nor "perpetual."                    See State v. Douglas, 123

Wis. 2d 13,        21-22,     365     N.W.2d 580         (1985)        (lead      opinion).

Rather,     its    scope    is     determined      objectively         as    "the    typical

reasonable person [would] have understood" it from "the exchange

between the officer and the suspect."                         Florida v. Jimeno, 500

U.S. 248, 251 (1991).              When the police rely on consent as their

justification for not getting a warrant, the State carries the

burden to demonstrate by clear and convincing evidence that the

search remained within the scope of that consent.                            See Reed, 384

Wis. 2d 469, ¶58; Douglas, 123 Wis. 2d at 22 (explaining that a

warrantless        search        exceeding       the      scope       of      consent     is
unreasonable).

      ¶71    The     lawfulness       of     the       Sheriff's       Office's      search

therefore turns on two sub-questions:                    (1) although he consented

to    specific       GBPD     personnel          downloading          his     cell    phone

information,       did     Burch    maintain       a   reasonable          expectation    of

privacy     in    that     information     such        that    the    Sheriff's      Office

review of it was a Fourth Amendment search; and, if so, (2) did

the Sheriff's Office act unreasonably by searching the GBPD's
download of Burch's cell phone data without a warrant, in light

of Burch's consent to the GBPD?

                                             5
                                                                     No.   2019AP1404-CR.rfd

 1.    Burch Maintained a Reasonable Expectation of Privacy in the
               GBPD's Download of His Cell Phone Data.
       ¶72    In   the    Fourth      Amendment        context,      the   United       States

Supreme Court has clearly expressed that cell phone data is in

an evidence class of its own because it "implicate[s] privacy

concerns far beyond those implicated by the search of" other

physical belongings.                Riley v. California, 573 U.S. 373, 393

(2014).       Cell phones are unique in that they are almost always

with    us     and       they       store      "vast       quantities       of        personal

information."          Id.     at    386.      Thus,     by   carrying      cell       phones,

people carry with them "a digital record of nearly every aspect

of their lives——from the mundane to the intimate."                              Id. at 395.

That digital record may include a person's internet "search and

browsing history" and "[h]istoric location information," see id.

at 395-96, allowing someone with access to that information to

"generate[] a precise, comprehensive record of a person's public

movements that reflects a wealth of detail about her familial,

political,      professional,          religious,       and    sexual      associations,"

see    United      States       v.         Jones,    565      U.S. 400,         415     (2012)

(Sotomayor, J.,          concurring).               Although      traditionally           most

private information was kept in one's home, advances in digital

technology      have     shifted      that     paradigm       such   that       searching    a

personal cell phone "would typically expose to the government

far    more     than     the        most     exhaustive       search       of    a     house."

Riley, 573 U.S. at 396-97.                   Accordingly, people have a unique

and heightened expectation of privacy in their cell phone data

that demands commensurate Fourth Amendment protection.                                See id.
at 386, 393; People v. Hughes, 958 N.W.2d 98, 112 (Mich. 2020)

                                               6
                                                              No.    2019AP1404-CR.rfd

("Riley distinguished cell-phone data from other items . . . in

terms of the privacy interests at stake.").

       ¶73    The   unique   privacy      expectation    in     cell      phone   data

informs why Burch's consent to the GBPD does not relieve the

Sheriff's Office of its obligation to get a warrant for its own

review.        Burch's   consent,    as    "the   typical     reasonable        person

[would] have understood" it, had the "expressed object" of the

GBPD   reviewing     messages   to     verify     his   alibi       for   the   GBPD's

investigation.       See Jimeno, 500 U.S. at 251.             The GBPD officer's

report explained that Burch "consented to Lt. Allen and I [two

GBPD officers]       looking at the text messages between him and

[Burch's acquaintance] last night and also indicated I could

take his phone to the department to have the information on it

downloaded."        Burch's signed consent form is also specific to

the "City of Green Bay Police Department" and indicated that

Burch gave certain members of the GBPD permission to search his

phone.       Critically absent from the report or the consent form is

any mention of any other law enforcement agency, the possibility
of the GBPD sharing the entirety of the downloaded data, or even

that Burch was consenting to the GBPD retaining indefinitely all

of his phone's information.          Cf. Douglas, 123 Wis. 2d at 21-22.

                                          7
                                                                 No.    2019AP1404-CR.rfd

       ¶74    Burch's consent was therefore limited to the GBPD for

the GBPD's investigation.3                See Terry, 392 U.S. at 25-26, 29

(requiring courts to interpret warrant exceptions as "confined

in scope" and "strictly circumscribed").                     With respect to other

agencies and their investigations, Burch maintained a reasonable

expectation of privacy in the data downloaded by the GBPD but

unrelated to its investigation, including his internet search

history and Google email account.                      See Carpenter, 138 S. Ct.

at 2217      (holding     that,   because        of   cell   phone     data's      "unique

nature,"      a     person   "maintains          a    legitimate       expectation       of

privacy"      in    the   data    even    after       consensually        giving    it   to

another party for a limited purpose); Hughes, 958 N.W.2d at 111

(concluding that the lawful seizure and search of certain cell

phone       information      does      not       "extinguish[]         that   otherwise

reasonable        expectation     of     privacy      in   the   entirety"      of   that

information).         Consequently, the Sheriff's Office's subsequent

review of Burch's data invaded Burch's reasonable expectation of

privacy such that it was a search under the Fourth Amendment.

  2.       The Sheriff's Office Acted Unreasonably in Searching the
               GBPD's Download of Burch's Cell Phone Data.
       ¶75    The    Sheriff's      Office       decided     that    no    warrant       was

required for its search after determining that Burch's consent

       The circuit court's determination that Burch placed no
       3

parameters on the scope of his consent is suspect given that his
conversation with the GBPD about his phone was strictly limited
to his text messages.     The categorical uniqueness of private
cell phone data requires circuit courts to take seriously the
admonition that exceptions to the warrant requirement like
consent be interpreted as "confined in scope" and "strictly
circumscribed." See Riley v. California, 573 U.S. 373, 382, 393
(2014); Terry v. Ohio, 392 U.S. 1, 25-26, 29 (1968).

                                             8
                                                                           No.    2019AP1404-CR.rfd

to the GBPD extended to the Sheriff's Office.                                But as discussed

above, Burch's "unequivocal and specific" consent extended only

to certain members of the GBPD, and only so they could review

his      text     messages      to    confirm          his        alibi.         See    Reed,      384

Wis. 2d 469, ¶8.             Burch         did        not     consent       to        all     of   the

information         on    his        phone     being         available           to     other      law

enforcement agencies for some later, unrelated investigation.

And      the    Sheriff's    Office        did        not    independently             get    Burch's

consent to search his cell phone information.

         ¶76    Given    those       facts,      no    reasonable          person       in    Burch's

position would have understood that his consent to the GBPD was

an    open      invitation      for    any     other         law    enforcement          agency     to

search his private information whenever it wanted to and without

a    warrant.        Therefore,        the     consent            exception      to     the    Fourth

Amendment's warrant requirement does not apply to the Sheriff's

Office's subsequent warrantless search of Burch's private cell

phone data for an unrelated investigation.                                   That search was

unreasonable and violated the Fourth Amendment.

    B.    Evidence of Burch's Google Location Data and His Internet
                  Search History Should Be Suppressed.
         ¶77    Having concluded that the Sheriff's Office's search

violated the Fourth Amendment, the next question is whether the

exclusionary        rule     applies;         that          is,     whether       excluding,       or

suppressing, the unlawfully obtained evidence would sufficiently

deter the same police conduct in the future.                                      Here, Burch's

Google location data and his internet search history should be
excluded because if they are not, other law enforcement agencies

are      likely    to    repeat      the     Sheriff's        Office's        unconstitutional

                                                 9
                                                                             No.    2019AP1404-CR.rfd

search    of    downloaded             cell    phone          data,    especially          given      the

ubiquity       of    cell     phones          and        the    increasing          prevalence            of

personal digital data in criminal investigations.

       ¶78     The     exclusionary            rule——that             evidence           obtained         in

violation       of    the     Fourth      Amendment            be     excluded          from    trial——

ensures      that     the     Fourth      Amendment's               right    to     be     free      from

unreasonable searches remains one "of substance rather than mere

tinsel."       Hoyer v. State, 180 Wis. 407, 415, 193 N.W. 89 (1923).

By excluding otherwise relevant evidence, "[t]he exclusionary

rule generally serves to 'deter deliberate, reckless, or grossly

negligent       conduct,          or     in     some          circumstances             recurring         or

systemic negligence.'"                  Blackman, 377 Wis. 2d 339, ¶68 (quoting

Herring v. United States, 555 U.S. 135, 150-51 (2009)).                                               The

rule    thus    incentivizes            "the     law       enforcement            profession         as    a

whole" to conduct itself "in accord with the Fourth Amendment."

Gates,    462       U.S.    at    261     n.15       (White,          J.,    concurring         in    the

judgment).

       ¶79     Given       that        critical          function,          the     United       States
Supreme Court has permitted deviation from the exclusionary rule

only    when    the    deterrent          value          of    excluding          the    evidence         is

"marginal" or "nonexistent" and outweighed by the social cost of

doing     so.              See,    e.g.,         United          States            v.     Leon,       468

U.S. 897, 913-17, 922 (1984).                    Such is the case when there is no

police misconduct to deter or when the police misconduct is

"isolated," "nonrecurring," and "attenuated."                                     See id. at 922;

Herring,       555     U.S.       at     137,       144.            For     example,        excluding
unlawfully      obtained          evidence          is    inappropriate             if    the   police

acted in objectively reasonable reliance on either a facially

                                                    10
                                                                        No.   2019AP1404-CR.rfd

valid warrant properly issued by a neutral, detached magistrate;

an    apparently         constitutional            statute;    or   a   binding     appellate

precedent.              See    Leon,    468    U.S. 897       (warrants);4      Illinois       v.

Krull,       480        U.S.    340     (1987)          (statutes);     Davis      v.    United

States, 564         U.S. 229,          239-41       (2011)     (appellate       precedents).

Likewise, exclusion is inappropriate when an arresting officer

acts in objectively reasonable reliance on either a judicial or

police employees' infrequent clerical mistake.                                See Arizona v.

Evans,       514         U.S. 1, 14-16             (1995)     (court       clerk        made    a

recordkeeping error regarding outstanding arrest warrants only

once "every three or four years"); Herring, 555 U.S. at 144-47

(police employees' clerical error in warrant database had never

happened before).              The common thread through each of these cases

is that the fault lies with someone who is not directly engaged

in the "competitive enterprise of ferreting out crime"; who has

"no    stake       in    the    outcome       of    particular      prosecutions."             See

Evans, 514 U.S. at 15.

       ¶80     Conversely,             the    exclusionary          rule      applies      when
evidence is unlawfully obtained due to an error made by law

enforcement.            See Leon, 468 U.S. at 923.               For instance, evidence

should be suppressed when law enforcement secures evidence based

on a facially deficient warrant, or when a warrant is issued

based on an officer knowingly or recklessly stating a falsehood

in the warrant affidavit.                      See id.        The same goes for when

police exceed a valid warrant's authority when executing it.

See id.        As for the police relying on statutory authority, the

       See also Massachusetts v. Sheppard, 468 U.S. 981, 988-91
       4

(1984).

                                                   11
                                                                       No.   2019AP1404-CR.rfd

exclusionary          rule      still         applies          when     police        officers

misinterpret and "act outside the scope" of a statute and when a

reasonable       officer       would    have       known      either    that    the    law    in

question is unconstitutional or that the conduct authorized by

the statute violates other clearly established law.                               Krull, 480

U.S.    at 355,       360    n.17.          Indeed,      the    rule    applies       even    to

unlawfully       negligent        police          conduct       when    the     conduct       is

"recurring or systemic."               E.g., Herring, 555 U.S. at 144.

       ¶81   The exclusionary rule applies in this case because it

was the Sheriff's Office's conduct that rendered unlawful its

search of Burch's cell phone, not some detached third party's.

There     was    no     statute        or        judicial      precedent        condoning     a

warrantless search of another agency's download of a person's

private cell phone data.                Instead, the Sheriff's Office judged

for    itself,    incorrectly,          that       the    Fourth      Amendment's      warrant

requirement      did     not    apply       to    Burch's      cell    phone    data.        The

unlawful conduct here——not obtaining a warrant to search Burch's

private cell phone data——is solely attributable to the Sheriff's
Office's detectives.             And because those detectives are directly

engaged in the "competitive enterprise of ferreting out crime,"

the exclusionary rule should apply.                      See Evans, 514 U.S. at 15.

       ¶82   Applying the rule is also justified because the record

demonstrates      that       warrantless          searches      of    private    cell    phone

information       are    commonplace,            and     therefore     likely     to    recur.

Officers from both the GBPD and the Sheriff's Office confirmed

that it is "very common" for agencies to share "full downloads"
of     private    cell       phones     with          other    agencies      without    first

obtaining a warrant, adding that their agencies "regularly" do

                                                 12
                                                                         No.    2019AP1404-CR.rfd

so.    This widespread neglect of the Fourth Amendment's warrant

requirement      is    just       the       kind       of    "systemic      negligence"          the

exclusionary rule is designed to correct.                            See Herring, 555 U.S.

at 144.      The exclusionary rule thus squarely applies here.

       ¶83    The    State's          counterarguments            are     unavailing.            Its

contention that the Sheriff's Office reasonably relied upon its

own determination regarding the scope of Burch's consent misses

the point.      It is not up to the police to determine the contours

of    an   exception       to    a     constitutional             requirement         restricting

their own conduct.               See Leon, 468 U.S. at 959 (Brennan, J.,

dissenting)         (presciently            lamenting         that      exceptions        to     the

exclusionary        rule    would          not    stay      "confined"         but    instead    be

wrongfully      extended        "to     situations           in   which     the      police     have

conducted a warrantless search solely on the basis of their own

judgment").           Moreover,            because          the    police       may     encounter

circumstances        that       are    on    the       margins     of    the    law     regarding

warrant      exceptions——as           is    the    case      here——police            officers    are

required to "err on the side of constitutional behavior" and get
a warrant.5         See United States v. Johnson, 457 U.S. 537, 561

       The State erroneously argues that the Sheriff's Office's
       5

search is akin to law enforcement's ability to take a "second
look" at physical evidence inventoried during a jail intake or
that it already lawfully seized.    See State v. Betterley, 191
Wis. 2d 406, 418, 529 N.W.2d 216 (1995); State v. Riedel, 2003
WI App 18, ¶16, 259 Wis. 2d 921, 656 N.W.2d 789.     But as the
United States Supreme Court explained in Riley, "cell phones, as
a category, implicate privacy concerns far beyond those
implicated" by physical objects. 573 U.S. at 393. And because
a "search of the information on a cell phone bears little
resemblance" to other types of searches, the rationales for
other searches do not extend to cell phone information. See id.
at 386.   Therefore, the State's arguments fail.   See People v.
Hughes, 958 N.W.2d 98, 111-15 (Mich. 2020).

                                                  13
                                                                 No.   2019AP1404-CR.rfd

(1982);    Blackman,       377    Wis. 2d 339,       ¶53    (warrantless      searches

executed outside any "clearly delineated" warrant exception are

"per se unreasonable" and "unlawful").                     The Sheriff's Office's

erroneous   determination          that    Burch's      consent    extended      to    the

Sheriff's    Office    is    no     justification          for   failing    to   get    a

warrant.

    ¶84     Nor is the Sheriff's Office relieved of its Fourth

Amendment duty to get a warrant simply because law enforcement

agencies    "regularly"          share    this    type     of    information.         The

pervasiveness of this practice is no defense to the exclusionary

rule; it is the reason to apply it.                        See Herring, 555 U.S.

at 144 (exclusion applies when unreasonable police conduct is

"recurring" or "systemic").               The same goes for the majority's

characterization of the Sheriff's Office's conduct as "by the

book."     Majority op., ¶22.             If following "the book" leads to

violations of the Fourth Amendment, then the exclusionary rule's

deterrent value is at its peak.                  Excluding evidence obtained by

following     such    an    unlawful       and     widespread      policy     provides
significant     societal         value     by    both      specifically      deterring

continued   adherence       to     an    unconstitutional        practice    and      more

broadly incentivizing police agencies to adopt policies in line

with the Fourth Amendment.6                See Wayne R. LaFave, 1 Search &

Seizure § 1.3(i) (6th ed. 2020).                  This is especially true when

    6  The State counters that because the Sheriff's Office may
have had access to Burch's Google email account and internet
search history via a lawful, independent source, that evidence
should   not  be   excluded.     See  State   v.  Carroll,   2010
WI 8, ¶¶44-45, 322 Wis. 2d 299, 778 N.W.2d 1. But the State has
forfeited that argument by failing to raise it below. See State
v. Counihan, 2020 WI 12, ¶25, 390 Wis. 2d 172, 938 N.W.2d 530.

                                           14
                                                                       No.    2019AP1404-CR.rfd

the Constitution already provides law enforcement with a simple

solution for how to lawfully obtain cell phone data:                                        get a

warrant.       See Riley, 573 U.S. at 403.

   C.    The Majority Opinion Has No Support in Fourth Amendment
                            Jurisprudence.
       ¶85     The majority opinion offers a contrary analysis that

ignores       the    novel    constitutional             problems      presented       by    cell

phone data, is inconsistent with the Fourth Amendment's text,

and undermines the exclusionary remedy.

       ¶86     The    majority       opinion's          analysis    reveals       a    lack    of

appreciation         for    the     fundamental          differences      between          digital

cell    phone       data    and    more     "traditional,"         non-digital         evidence

that    law    enforcement          might       share    with   other        agencies.         The

Fourth Amendment treats cell phone data differently because it

often contains nearly all the "privacies of [a person's] life,"

such that "any extension" of Fourth Amendment principles "to

digital data has to rest on its own bottom."                                 See Riley, 573

U.S. at 393, 403 (quoting another source); Carpenter, 138 S. Ct.

at 2219       (explaining         that     Fourth       Amendment      jurisprudence         must

account       for     the    "seismic           shifts     in    digital       technology").

Accordingly, it is a grave analytical error to "mechanically

apply[]" to cell phone data Fourth Amendment rationales that

were    developed          without       such    invasive       technologies          in    mind.

Carpenter,          138    S. Ct.     at    2219;        see    also    Riley,        573     U.S.

at 400-01 (rejecting the argument that the police can search

cell phone data under the same rationale that allows them to
obtain "the same information from a pre-digital counterpart").

Or, as the United States Supreme Court put it, treating cell

                                                 15
                                                                               No.    2019AP1404-CR.rfd

phone data the same as its non-digital analogues "is like saying

a   ride      on    horseback             is    materially         indistinguishable            from     a

flight to the moon.                      Both are ways of getting from point A to

point    B,       but    little           else      justifies         lumping     them       together."

Riley,     573      U.S.       at    393.           The       majority   opinion,           however,   is

content to toss a saddle on a spaceship and call it a horse.

Nowhere does the majority opinion account for Burch's special

privacy interest in his cell phone data, leaving a tremendous

hole in its exclusionary rule analysis.

      ¶87         More   troubling             is    the      majority's       disregard        for    the

Fourth Amendment's text.                         It is bedrock Fourth Amendment law

that search warrants are generally required and that a search

without       a    warrant          is    per       se    unlawful.        See,       e.g.,     City    of

Ontario       v.     Quon,          560    U.S. 746,            760    (2010);        Blackman,        377

Wis. 2d 339,            ¶53.         The       majority's         assertion          that    "there    is

nothing concerning under current Fourth Amendment doctrine with

how     the       Sheriff's          Office          detectives          conducted          themselves"

shockingly discards this well-settled principle.                                            Indeed, the
majority          opinion      fails       to       even      mention    the    presumption           that

warrantless searches violate the Fourth Amendment.

      ¶88         But worse than mere silence, the majority's refusal to

apply the exclusionary rule flips this presumption on its head.

According to the majority, if "no case from this court or the

federal courts" directs the police to get a warrant, then the

police act "reasonably" in                           not getting a warrant.                    Majority

op., ¶23.          The majority appears to create a new prerequisite for
applying the exclusionary rule, holding that it applies only if

a court has previously declared that the police conduct at issue

                                                         16
                                                                    No.    2019AP1404-CR.rfd

is    unconstitutional.              Imposing       this    hurdle        undermines          the

exclusionary        remedy    for        Fourth    Amendment    violations              and    is

directly contrary to both our and the United States                                     Supreme

Court's Fourth Amendment jurisprudence.

       ¶89     All of which makes inexcusable the majority opinion's

refusal      to     address    the       constitutionality          of     the     Sheriff's

Office's       search.       Despite      law     enforcement's      admittedly           "very

common" practice of sharing with other agencies entire downloads

of    private      cell    phone    data,    that       recurring    Fourth        Amendment

violation will continue with impunity unless and until the court

engages      with    the    specific       Fourth       Amendment    issue        raised      by

private cell phone information.                   By skipping straight to whether

the   exclusionary         rule    applies,       the    majority    opinion        deprives

aggrieved         defendants——and         future    courts——of        the        very     prior

precedent now necessary to remedy law enforcement's continued

unconstitutional conduct:

       Forgoing a knotty constitutional inquiry makes for
       easier sledding, no doubt. But the inexorable result
       is     "constitutional     stagnation"——fewer     courts
       establishing law at all, much less clearly doing
       so, . . . [creating a] Catch-22.      [Defendants] must
       produce precedent even as fewer courts are producing
       precedent.     Important constitutional questions go
       unanswered precisely because no one's answered them
       before. Courts then rely on that judicial silence to
       conclude there's no equivalent case law on the
       books. . . . If    courts    leapfrog   the   underlying
       constitutional merits in cases raising novel issues
       like digital privacy, then constitutional clarity——
       matter-of-fact guidance about what the Constitution
       requires——remains         exasperatingly        elusive.
       Result: gauzy       constitutional     guardrails     as
       technological innovation outpaces legal adaptation.
Zadeh     v.      Robinson,        928    F.3d 457,        479-80     (5th        Cir. 2019)

(Willet, J., concurring), cert. denied, 141 S. Ct. 110 (2020).
                                             17
                                                                            No.   2019AP1404-CR.rfd

Together with its new prior-precedent requirement, the majority

opinion's     avoidance            of       the     Fourth       Amendment          issues      here

perpetuates       a    cycle       of       diminished         police    accountability         and

courts' unwillingness to address it.

      ¶90    Given that the Fourth Amendment law specific to cell

phone data is undeveloped, this court should be providing "clear

guidance     to        law     enforcement               through        categorical         rules."

Riley, 573    U.S.       at    398;          see    also       Michigan      v.    Summers,     452

U.S. 692,    705       n.19    (1981)         (explaining          that      clear     "workable"

rules are necessary so that difficult Fourth Amendment questions

are   not    resolved         in    an        "ad       hoc,    case-by-case          fashion    by

individual police officers") (quoting another source)).                                       If a

law   enforcement        agency         wishes       to    search       a    person's       private

information, such as cell phone data, and the person did not

consent to that agency's search, the agency must get a warrant.

                                    III.          CONCLUSION

      ¶91    The Sheriff's Office should have obtained a warrant to

search Burch's private cell phone data.                           Because it did not, the
evidence     it       found    as       a     result       of    that       search     should    be

suppressed.           The majority's refusal to apply the exclusionary

rule is incompatible with our Fourth Amendment jurisprudence and

perverts     the       long-standing              bedrock       requirement          that    police

obtain a warrant to search private information.                                      I therefore

respectfully dissent from that part of the majority opinion.

      ¶92    I am authorized to state that Justice JILL J. KAROFSKY
joins this opinion and that Justice ANN WALSH BRADLEY joins this

opinion except for footnote 1.

                                                   18
     No.   2019AP1404-CR.rfd

19
                                                                              No.   2019AP1404-CR.awb

       ¶93   ANN WALSH BRADLEY, J.                        (dissenting).             Ubiquitous use

does not mean the average wearer of a Fitbit knows how it works.

Nor does ubiquitous use indicate reliability sufficient to be

admissible in a court of law.

       ¶94   An average jury member would likely know what a Fitbit

is and what it does.              Of course, as relevant here, it counts the

wearer's steps.            But that isn't the question.                             In determining

whether expert testimony is required, the relevant inquiry is

how a Fitbit counts the wearer's steps and then ultimately,

whether it does so with sufficient reliability.

       ¶95   How      does        it        work?          A    Fitbit          device       uses     a

microelectronic         triaxial            accelerometer           to    capture       a   person's

body motion in three-dimensional space and record related data.

This   motion      data      is    then        analyzed        by    utilizing          proprietary

algorithms to surmise patterns and thus to identify daily steps

taken.

       ¶96   Is it sufficiently reliable to be admitted as evidence

in court?        I don't know.               But, I do know that the answer does
not lie in its ubiquitous use.

       ¶97   I   also      know        that    absent       expert        testimony         there   is

insufficient       foundation           in     this       record     for        the    majority     to

determine,       in   essence,          that        a    presumption           of     accuracy      and

reliability attends the underlying technology of a Fitbit.                                          The

error of such a presumption is made manifest by reference to an

overarching        analysis            of     67        studies          on     Fitbit      accuracy

disseminated          by     the        National           Center             for     Biotechnology
Information      (NCBI),      under           the       auspices     of       the   U.S.    National

                                                    1
                                                             No.    2019AP1404-CR.awb

Institutes of Health (NIH).           The researchers found that Fitbit

devices were "likely to meet acceptable accuracy for step count

approximately half the time."         Lynne M. Feehan, et al., Accuracy

of Fitbit Devices:      Systematic Review and Narrative Syntheses of

Quantitative                                                                   Data,

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6107736/ (2018).

    ¶98     In citing this study, I neither endorse nor disclaim

its conclusions.       It suggests, however, when a compilation of

studies   indicates    acceptable     accuracy       is    met     only   "half    the

time,"    that    something    may    be   amiss          with     the    majority's

presumption of accuracy and reliability.

    ¶99     Expert    testimony      is    required         when     matters       are

presented that are "unusually complex."                   White v. Leeder, 149

Wis. 2d 948, 960, 440 N.W.2d 557 (1989).               Movement measured by a

"microelectronic      triaxial       accelerometer"          and     analyzed       by

proprietary algorithms certainly fits that bill.

    ¶100 In my view, the technology underlying a Fitbit is not

within    the    ordinary   experience     of   an     average       jury    member.
Fitbits and other wearable devices may be ubiquitous, but it

does not follow from this premise that the technology underlying

their use is not "unusually complex."

    ¶101 Expert       testimony      assists     the       trier     of     fact    to

understand the evidence and to determine a fact in issue.                          The

accuracy of the number of steps recorded on Douglass Detrie's

Fitbit is certainly a fact in issue.                 Thus, expert testimony

should have been required to assist the jury in understanding
the technology and assessing its reliability.

                                       2
                                                                         No.    2019AP1404-CR.awb

       ¶102 Invoking a deferential standard, it is not unusual for

an     appellate       court       to    do    only      a    cursory      analysis            of   an

evidentiary issue.                But this is not the usual case and a more

nuanced analysis is required.

       ¶103 This case presents a groundbreaking question.                                       To my

knowledge, this is the first appellate court decision in the

country     to     conclude         that       Fitbit        step-counting           evidence       is

admissible       absent      expert       testimony          explaining        how    the       device

works.     The parties have not cited, and I have not found, any

case    making        such    a    proclamation.               The      majority's         analysis

provides    a     slim       reed       upon    which        to   support       such       a    novel

determination.

       ¶104 Rather than allowing evaluation of the question, the

majority cuts off the debate.                       It essentially rubber stamps the

circuit     court's          erroneous         analysis           and    declares          Fitbit's

technology       to    be    simple       enough        to   be    presented         as    evidence

without     the        benefit          of     an       expert       witness         or        further

consideration of its reliability.
       ¶105 Although I join Justice Dallet's dissent, concluding

that the search of Burch's cell phone at issue violated his

Fourth Amendment rights and that the good faith exception to the

warrant requirement does not apply, I do not join footnote 1

that     concurs       with       the    majority's           analysis         of    the       Fitbit

evidence.        Because I conclude that the circuit court erroneously

admitted    the        Fitbit       evidence        without       an     expert       witness       to

establish the reliability of the science underlying the Fitbit
technology, I respectfully dissent.

                                                    3
                                                                 No.   2019AP1404-CR.awb

                                        I

    ¶106 I briefly recount the facts that are relevant to the

issue on which I write:        the admission of the Fitbit evidence.

    ¶107 As      the   majority       opinion       sets    forth,       the     initial

suspect in the crime at issue here was Douglass Detrie, the

victim's   boyfriend.          Majority         op.,       ¶4.          However,      the

investigation shifted after police learned that Detrie's Fitbit

device had recorded only 12 steps during the time the homicide

was committed.     Burch was ultimately arrested and charged.

    ¶108 The       State     sought     to    present        evidence          regarding

Detrie's Fitbit, and Burch moved to exclude it.                        Id., ¶11.       As

relevant   here,    Burch    contended       that    the     State      must    present

expert testimony to establish the reliability of the science

behind the Fitbit device.        Id.1

    ¶109 The circuit court granted Burch's motion in part and

denied it in part.          Specifically, the circuit court excluded

Fitbit evidence related to sleep monitoring, but it allowed the

admission of the step-counting data without the testimony of an
expert regarding the science underlying the Fitbit technology.

Id., ¶11 & n.3.

    ¶110 In the circuit court's estimation, a Fitbit is more

akin to an electronic monitoring device (which does not require

expert   testimony,    see    State     v.   Kandutsch,          2011    WI     78,   336

    1  Burch made several additional arguments, including an
assertion that Fitbit's records were not properly authenticated,
which he renews on appeal.      Because I determine that expert
testimony was necessary to admit the evidence in question, I do
not reach Burch's arguments regarding authentication.

                                        4
                                                     No.   2019AP1404-CR.awb

Wis. 2d 478, 799 N.W.2d 865) than to a preliminary breath test

(which   requires     expert   testimony,   see   State    v.    Doerr,     229

Wis. 2d 616, 599 N.W.2d 897 (Ct. App. 1999)).              Similarly, the

circuit court distinguished Fitbit data from DNA, fingerprint

analysis, blood alcohol content tests, tool mark evidence and

accident   reconstruction      because   "few   people    encounter      those

things in their everyday life."

    ¶111 Comparing a Fitbit to an electronic monitoring device,

the circuit court stated that a Fitbit is "passively worn by a

person," and the device collects data "based on that person's

movements, which is then transmitted and recorded.              There is no

active manipulation by the wearer to achieve the results; the

results are simply a record of the wearer's movements, i.e.,

their location or the number of steps they took."               Thus, in the

circuit court's view "the step-counting feature of the Fitbit

Flex,    like   the   [electronic   monitoring    device],       is   not   so

unusually complex or esoteric that the jury will require the aid

of expert testimony to interpret the information."
    ¶112 At trial, because it was not required to provide an

expert to introduce the data from Detrie's Fitbit, the State

relied upon the testimony of Tyler Behling, a computer forensic

crime analyst with the Brown County Sheriff's Office.                 Although

Behling claimed to have knowledge of how a Fitbit works "on a

high level," he did not know the answer when asked how a Fitbit

and a Bluetooth device send information from one to the other,

how Fitbit stores its data, whether Fitbit data can be edited,

                                     5
                                                                         No.    2019AP1404-CR.awb

whether the device would register steps while it is not being

worn, or what a Fitbit's error rate is.

      ¶113 Despite the dearth of technical testimony regarding

how   a   Fitbit       actually        works,          the    majority     now    affirms      the

circuit court's determination.                         It concludes that "[g]iven the

widespread availability of Fitbits and other similar wireless

step-counting          devices        in     today's          consumer     marketplace,        the

circuit court reasonably concluded Detrie's Fitbit was not so

'unusually complex or esoteric' that the jury needed an expert

to understand it."          Majority op., ¶31.

                                                   II

      ¶114 It has long            been the law that expert testimony is

required when a matter involves "special knowledge or skill or

experience on subjects which are not within the realm of the

ordinary        experience       of        mankind,          and   which    require       special

learning, study and experience."                         Cramer v. Theda Clark Mem'l

Hosp.,     45     Wis. 2d 147,             150,    172        N.W.2d 427       (1969).         "The

requirement of expert testimony is an extraordinary one," and
should    be     applied     "only          when       unusually     complex      or     esoteric

issues are before the jury."                     White, 149 Wis. 2d at 960.

      ¶115 "In         considering              what      constitutes          the     'ordinary

experience of mankind'——i.e. the average juror——courts have not

tailored        this    standard           to     the     lowest      common      denominator.

Rather, courts attempt to evaluate, on a case-by-case basis,

whether    expert       testimony           is     required        because      the    issue    is

outside     the     realm    of        lay        comprehension."              Kandutsch,      336
Wis. 2d 478, ¶29.

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      ¶116 The circuit court here determined that the technology

underlying     a    Fitbit    is     not     outside     the     realm      of     lay

comprehension.       It compared a Fitbit to a watch in that "the

public generally understands the principle of how it functions

and accepts its reliability without knowing the exact mechanics

of its internal workings."          Further, it determined that a Fitbit

is not subject to "active manipulation by the wearer to achieve

the results; the results are simply a record of the wearer's

movements, i.e., their location or the number of steps they

took."

      ¶117 But     the   expert    testimony    standards       do    not   rest    on

ubiquity.     Instead, they rest on the complexity of the subject

matter.     Although many members of the jury may have been wearing

Fitbits or similar devices, such a fact would not inform the

question of whether those jury members understand how a Fitbit

works or whether the technology is reliable.

      ¶118 What does the average person really know about how a

Fitbit works, much less its reliability?               As one study described
it, "Fitbit devices use a microelectronic triaxial accelerometer

to capture body motion in 3-dimensional space, with these motion

data analyzed using proprietary algorithms to identify patterns

of motion to identify daily steps taken, energy expenditure,

sleep, distance covered, and time spent in different intensity

of   activities."        Feehan,   et    al.,   supra.         According     to    the

majority,    the   average   juror      would   understand,      without      expert

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testimony,      not     only     what       a     "microelectronic            triaxial

accelerometer" is, but how it works.              Really?2

      ¶119 If    the   State   had    presented     an    expert,       that    expert

would have had to meet the requirements for expert testimony

established     by    the   United   States     Supreme      Court      in   Daubert.3

Pursuant to the        Daubert standard, as codified in Wis. Stat.

§ 907.02(1),4 the circuit court must act as a gatekeeper and make

a   threshold   determination        that   the   testimony        is   reliable    in

order for it to be presented at trial.               State v. Dobbs, 2020 WI

64, ¶43, 392 Wis. 2d 505, 945 N.W.2d 609.                 By not requiring the

State to present an expert, the circuit court and the majority

allow the State to skirt this initial reliability determination.

      ¶120 There are various ways in which threshold reliability

can be demonstrated.         See 7 Daniel D. Blinka, Wisconsin Practice

Series:     Wisconsin Evidence § 702.402 (4th ed. 2020).                     There may

      2Further, the intricacies of Fitbit's technology are
"proprietary," setting up an additional roadblock to the jury's
full knowledge and full understanding of how the device works.
See State v. Loomis, 2016 WI 68, ¶66, 371 Wis. 2d 235, 881
N.W.2d 749 (explaining that "proprietary nature" has been
invoked to prevent disclosure of certain information).
      3   Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993).
      4   Wisconsin Stat. § 907.02(1) provides:

      If   scientific,   technical,   or  other   specialized
      knowledge will assist the trier of fact to understand
      the evidence or to determine a fact in issue, a
      witness qualified as an expert by knowledge, skill,
      experience,   training,   or  education,  may   testify
      thereto in the form of an opinion or otherwise, if the
      testimony is based upon sufficient facts or data, the
      testimony is the product of reliable principles and
      methods, and the witness has applied the principles
      and methods reliably to the facts of the case.

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be    a    statute     indicating          that       certain     tests          or    methods        are

admissible.            See,      e.g.,       Wis.      Stat.      § 885.235            (addressing

chemical       tests       for       intoxication).              There           is    no    statute

addressing Fitbit evidence.

          ¶121 We can also look to court precedent which has already

determined certain principles to be reliable.                                See, e.g., State

v.    Hanson,        85     Wis. 2d 233,              244,      270        N.W.2d 212            (1978)

(discussing      the       reliability          of    the    underlying           principles           of

speed radar detection that employs the Doppler effect).                                               The

reliability      of       Fitbit's      step      counting       capability            is    a    novel

issue, so there is no precedent on point.

          ¶122 Stipulations           or        judicial        notice           may        also       be

appropriate      when       a    fact      is    "capable       of     accurate          and       ready

determination         by     resort        to     sources       whose        accuracy            cannot

reasonably be questioned."                    Wis. Stat. § 902.01(2)(b).                         Again,

these do not fit the present scenario——the reason we are here is

because the parties do not agree and Burch reasonably questions

the accuracy of Fitbit's step count.
          ¶123 Finally,         if    none      of     the   above         proves       to       be    an

acceptable avenue to demonstrate the accuracy and reliability of

the   scientific          principles         sufficient      to       be    accorded         a    prima

facie presumption, expert testimony is necessary to explain the

underlying       scientific           principles         and      to       demonstrate            their

reliability.         Here, no expert was presented.

          ¶124 The evidentiary process requires that the scientific

principles be presented to the court before the evidence is
determined to be reliable.                   In a court of law, process matters.

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Without     fulfilling        one     of      these     avenues,          the      threshold

reliability determination cannot be made.

       ¶125 And what of Fitbit's reliability?                         Such reliability

can depend on a number of factors, such as whether the user has

self-manipulated the data, if the Fitbit is temporarily removed,

where on the body the device is worn, or the type of physical

activity in which the wearer is engaged.                      Feehan, et al., supra;

Katherine E. Vinez, The Admissibility of Data Collected from

Wearable Devices, 4 Stetson J. Advoc. & L. 1, 16 (2017).                                  In a

comprehensive aggregation of 67 different studies, researchers

found that "[c]onsistent evidence indicated that Fitbit devices

were     likely    to     meet      acceptable        accuracy        for       step    count

approximately half the time."                 Feehan, et al., supra.                   Yet in

the view of the majority and of the circuit court, an expert is

not    necessary    to    establish        the   reliability         of    Detrie's       step

count——the       Fitbit    evidence     can      go   before     the       jury     with    no

technical or scientific explanation.

       ¶126 Indeed,       questions        arise      about    the        reliability       of
wearable       devices    despite     their       widespread         acceptance.           See

Vinez, supra, at 16.                If reliability questions exist, where

better    than    the     circuit     court      to   present    the        case    for    and

against such reliability?              Instead of remanding to the circuit

court    for     evaluation      of   the     question,        the    majority         curtly

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declares        Fitbit's   technology    to   be     simple   enough    to   be   put

before a jury without the benefit of an expert.5

       ¶127 When new and popular devices emerge, courts should be

wary       of   blindly    accepting   the    data    they    produce    without   a

thorough examination of the underlying technology.                        "Machines

warrant no blind faith, and whatever trust they receive must be

earned through the crucible of the rules of evidence."                         Brian

Sites, Machines Ascendant:             Robots and the Rules of Evidence, 3

Geo. L. Tech. Rev. 1, 1-2 (2018).                     In many cases, such an

examination will require an expert.                In my view, this is such a

case.

       ¶128 Rather than break new ground as does the majority, I

would proceed with caution.               Basing the necessity of expert

testimony on ubiquity rather than complexity sets a dangerous

path.

       ¶129 For the foregoing reasons, I respectfully dissent.

       See Nicole Chauriye, Wearable Devices as Admissible
       5

Evidence:   Technology is Killing our Opportunities to Lie, 24
Cath. U. J. L. & Tech. 495, 517 (2016) (arguing that "the trier
of fact would greatly benefit from mandated expert testimony to
explain the accuracy and details of the data recorded by the
wearable technology").

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