                FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,              No. 13-10146
            Plaintiff-Appellee,
                                          D.C. No.
               v.                   2:11-cr-02265-JAT-3

RAFIQ ALBERT BROOKS,
         Defendant-Appellant.            OPINION


      Appeal from the United States District Court
               for the District of Arizona
   James A. Teilborg, Senior District Judge, Presiding

                Argued and Submitted
     September 8, 2014—San Francisco, California

               Filed November 24, 2014

      Before: Mary M. Schroeder, John B. Owens,
       and Michelle T. Friedland, Circuit Judges.

              Opinion by Judge Friedland
2                  UNITED STATES V. BROOKS

                           SUMMARY*


                          Criminal Law

    The panel affirmed the defendant’s convictions for
possession with intent to distribute marijuana on November
17, 2011, and conspiracy to possess marijuana with intent to
distribute; reversed his conviction for possession with intent
to distribute marijuana on November 9, 2011; and remanded
to the district court to determine whether resentencing is
appropriate.

    The panel held that admission of photographs of a parcel
seized at the post office did not violate the Confrontation
Clause because the photographs were not “witnesses” against
the defendant.

    The panel held that admission of statements by a postal
supervisor, who did not testify, violated the Confrontation
Clause because the statements were testimonial and offered
for their truth, and there is no contention of unavailability or
that the defendant had a prior opportunity to cross-examine
the supervisor. The panel exercised its discretion to overlook
the government’s waiver as to harmlessness, and held that the
error was harmless as to the November 17 possession-with-
intent- to-distribute conviction and the conspiracy conviction.
The panel declined to find the error harmless as to the
November 9 count.




  *
    This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                 UNITED STATES V. BROOKS                     3

    The panel rejected as foreclosed the defendant’s
contention that the district court erred by denying his motion
to suppress evidence obtained by warrantless GPS
monitoring, and concluded that the district court did not abuse
its discretion by denying the defendant a minor participant
adjustment at sentencing.

    The panel left it for the district court to determine on
remand whether the defendant’s sentence for the remaining
convictions should be adjusted, and dismissed as moot the
defendant’s motion to remand based on changes to the
Sentencing Guidelines.


                         COUNSEL

D. Stephen Wallin (argued), The Wallin Law Firm, Phoenix,
Arizona, for Defendant-Appellant.

Mark S. Kokanovich (argued), Deputy Appellate Chief; John
S. Leonardo, United States Attorney; Michael A. Lee,
Assistant United States Attorney, Office of the United States
Attorney, Phoenix, Arizona, for Plaintiff-Appellee.
4                UNITED STATES V. BROOKS

                         OPINION

FRIEDLAND, Circuit Judge:

    Rafiq Brooks appeals his convictions on one count of
conspiracy to possess marijuana with intent to distribute and
two counts of possession of marijuana with intent to
distribute. At Brooks’s jury trial, the government introduced
out-of-court statements by a nontestifying post office
supervisor and photographs of a seized package that was the
subject of those statements. Brooks argues that the admission
of this evidence violated his rights under the Confrontation
Clause of the Sixth Amendment. We conclude that admission
of the photographs did not violate the Confrontation Clause,
but that admission of the postal supervisor’s statements did,
and we reverse the possession conviction that depended on
those statements.

                       I. Background

                              A.

    In March 2011, a task force of DEA officers and local law
enforcement began investigating a group of individuals
suspected of shipping marijuana through the mail. The leader
of the investigation, Officer Kurt Kinsey, focused
surveillance on an apartment in Glendale, Arizona. On three
occasions in August and September 2011, law enforcement
observed people loading boxes into a vehicle at the Glendale
apartment and then driving to a post office. On each
occasion, the task force enlisted the help of U.S. Postal
Inspector Jeff Agster to contact the post office and search the
suspected parcels. Marijuana was found each time.
                UNITED STATES V. BROOKS                     5

     Shortly after a traffic stop in late September in which
officers discovered two suspected conspirators with a parcel
containing marijuana, the task force observed the Glendale
apartment being cleaned out—numerous boxes, bags of
packing peanuts, and other packaging materials were brought
down and loaded into a car. Officers continued to observe the
suspected leader of the conspiracy, Koy Williams, at the
Glendale apartment, leading them to believe that Williams
still lived there.

    On the morning of November 9, 2011, Officer Kinsey
observed two men exiting the Glendale apartment and
entering a silver Buick. Kinsey recognized one of the men as
Koy Williams. The other man was dressed in a long-sleeve
blue dress shirt, dark-colored dress pants, and a tie. Kinsey
followed the silver Buick to an apartment in Phoenix.

    Later that morning, Kinsey followed the Buick from the
Phoenix apartment to Glendale, where he saw the Buick’s
driver enter a post office with a box. Kinsey contacted Agster
and relayed the mailer’s attire—long-sleeve blue dress shirt,
dress pants, and a tie. Agster, in turn, telephoned the
supervisor of the post office and conveyed the same
information. The supervisor confirmed the suspect’s
presence in the post office and, either later in the same
conversation or in a subsequent one, gave Agster mailing
information, including a tracking number, for the parcel that
the suspect had dropped off. Acting upon that information,
Agster obtained a warrant, searched the identified parcel
while taking pictures, and found marijuana. Meanwhile, a
different task force member, Special Agent John Nelson,
followed the Buick from the post office to a grocery store,
where he was able to observe the blue-shirted driver from a
short distance.
6                UNITED STATES V. BROOKS

    On November 17, 2011, officers arrested Brooks and four
others at the Phoenix apartment. A bag next to Brooks
contained $1,807 in cash, and he admitted during the arrest
that the silver Buick was his rental car. A protective sweep
of the apartment revealed bales of marijuana on the kitchen
counter and packaging supplies throughout the apartment.
One of the arrestees had three delivery receipts on his person;
the three corresponding parcels were intercepted en route to
New York and found to contain marijuana. After obtaining
a warrant, officers returned to the Phoenix apartment and
found two boxes of marijuana that were packed and ready for
shipment, thirteen delivery confirmation receipts in a cereal
box, and a Glock 17 handgun.

    The Glendale apartment was also searched. Unlike the
Phoenix apartment, which contained little furniture, the
Glendale apartment appeared to be lived in. Identification
documents for Brooks were found in one of the bedrooms,
along with packaging materials and a magazine for a Glock
17 handgun. The bedroom’s closet contained a blue dress
shirt, a pair of dark slacks, and a tie.

                              B.

    A grand jury indicted Brooks for conspiracy to possess
marijuana with intent to distribute, possession of marijuana
with intent to distribute on November 9 (the date of the
mailing at the Glendale post office), and possession of
marijuana with intent to distribute on November 17 (the date
of arrest at the Phoenix apartment). At trial, the prosecution
introduced evidence of the clothing in Brooks’s closet and of
his connection to the silver Buick to show that Brooks was
the mailer on November 9. Agent Nelson made an in-court
identification of Brooks as the man wearing a blue dress shirt
                 UNITED STATES V. BROOKS                    7

and dark slacks that he had followed to the grocery store from
the post office.

    The prosecution also sought to tie the man in the blue
shirt to the parcel containing marijuana. To that end,
Inspector Agster testified regarding his communication with
the post office supervisor on November 9:

       Prosecution: Let’s move forward to
                    November 9, 2011. Were you
                    contacted again by task force
                    members regarding another
                    parcel related to this
                    investigation?

       Agster:         Yes.

       Prosecution: What information were you
                    given at that time?

       Agster:         The information on this was
                       they were following another
                       subject who went to the
                       Glendale Arrowhead Post
                       Office in Glendale, Arizona.

       Prosecution: Did you contact the supervisor
                    of that post office?

       Agster:         Yes, I did.

       Prosecution: And in real time did you relate
                    to him the information
                    regarding the individual?
8                UNITED STATES V. BROOKS

       Agster:        Yes. I was provided with a
                      description of the subject that
                      was going in to mail parcels
                      and I relayed that information
                      to the supervisor as well.

       Prosecution: That same day did you obtain
                    that parcel?

       Agster:        I did.

       Prosecution: How did you know that was
                    the same parcel that had been
                    mailed earlier that day?

       Agster:        The information that was
                      provided to me over the
                      phone. The tracking number
                      as well as the mailing
                      information was the same
                      when I got there to pick up the
                      parcel.

The defense objected to this testimony—and to the admission
of photographs depicting Agster’s search of the parcel—on
Confrontation Clause grounds. The district court overruled
the objection. The postal supervisor never testified.

     The jury convicted Brooks on all counts. The district
court sentenced Brooks to 110 months on the conspiracy
count and 60 months on each of the possession counts, with
all terms to run concurrently.
                 UNITED STATES V. BROOKS                       9

                  II. Confrontation Clause

    The Confrontation Clause of the Sixth Amendment
provides that “[i]n all criminal prosecutions, the accused shall
enjoy the right . . . to be confronted with the witnesses against
him.” Brooks contends that Inspector Agster’s testimony
conveying out-of-court statements of the nontestifying postal
supervisor, as well as photographs of the parcel seized at the
Glendale post office, violated the Confrontation Clause.

    We review alleged violations of the Confrontation Clause
de novo. United States v. Nguyen, 565 F.3d 668, 673 (9th
Cir. 2009).

                               A.

    We reject Brooks’s argument that admitting photographs
of the seized parcel violated the Confrontation Clause. As the
Supreme Court explained in Crawford v. Washington, the
Confrontation Clause “applies to ‘witnesses’ against the
accused—in other words, those who ‘bear testimony.’”
541 U.S. 36, 51 (2004). “Testimony, in turn, is typically a
solemn declaration or affirmation made for the purpose of
establishing or proving some fact.” Id. (internal quotation
marks and brackets omitted). The photographs of the seized
parcel were not “witnesses” against Brooks. They did not
“bear testimony” by declaring or affirming anything with a
“purpose.” Therefore, their admission did not violate the
Confrontation Clause. See United States v. Lopez-Moreno,
420 F.3d 420, 436 (5th Cir. 2005) (holding that admission of
a voter identification card did not violate the Confrontation
Clause because it did not involve a witness bearing
testimony).
10               UNITED STATES V. BROOKS

                               B.

    Allowing Inspector Agster to testify about the postal
supervisor’s statements, on the other hand, did violate the
Confrontation Clause. In Crawford, the Supreme Court held
that the Confrontation Clause bars “admission of testimonial
statements of a witness who did not appear at trial” if the
statements are offered to “establish[] the truth of the matter
asserted,” unless the witness is unavailable and the defendant
has had a prior opportunity for cross-examination. 541 U.S.
at 53–54, 59–60 n.9. In other words, absent unavailability
and a prior chance for cross-examination, the Confrontation
Clause forbids a statement of a nontestifying witness that is
testimonial and offered for its truth.

     1. Inspector Agster conveyed out-of-court statements.

     There is no doubt that Agster’s testimony introduced
“statements” of the postal supervisor. Although the
government emphasizes that the “actual statements” of the
supervisor were not offered in testimony, out-of-court
statements need not be repeated verbatim to trigger the
protections of the Confrontation Clause. Rather, we have
explained that “out-of-court statements admitted at trial are
‘statements’ for the purpose of the Confrontation Clause . . .
if, fairly read, they convey to the jury the substance of an out-
of-court, testimonial statement of a witness who does not
testify at trial.” Ocampo v. Vail, 649 F.3d 1098, 1109–10
(9th Cir. 2011). Agster’s testimony conveyed the substance
of the postal supervisor’s statements. Agster testified that he
telephoned the supervisor and provided a description of the
suspect, and then later searched a particular parcel with the
tracking number and mailing information he had been
provided over the phone as identifying the package mailed by
                    UNITED STATES V. BROOKS                             11

the suspect. By conveying the substance of what the
supervisor said, Agster introduced “statements” for the
purpose of the Confrontation Clause, even though he did not
quote the supervisor verbatim.

      2. The statements were testimonial.

    The postal supervisor’s statements also were testimonial.
In the jointly decided cases of Davis v. Washington and
Hammon v. Indiana, the Supreme Court held that statements
made in the course of questioning by law enforcement “are
testimonial when the circumstances objectively indicate that
there is no . . . ongoing emergency, and that the primary
purpose of the interrogation is to establish or prove past
events potentially relevant to later criminal prosecution.”
547 U.S. 813, 822 (2006).1 Stated differently, courts must
consider whether a statement was “procured with a primary


  1
    In its post-Crawford cases, the Supreme Court has described a range
of interactions involving law enforcement personnel as “interrogations,”
including some that involved less formality than the term typically
connotes. For instance, Davis referred to a telephone conversation
between a 911 operator and a domestic abuse victim as an interrogation,
547 U.S. at 826, and Michigan v. Bryant did the same for an interaction
between police officers and a dying gunshot victim in a gas station
parking lot, 131 S. Ct. 1143, 1150 (2011). See also Crawford, 541 U.S.
at 53 n.4 (“We use the term ‘interrogation’ in its colloquial, rather than
any technical legal, sense.”). The Supreme Court has made clear,
however, that a statement need not be produced by “interrogation” in order
to be testimonial. See Davis, 547 U.S. at 822 n.1 (“The Framers were no
more willing to exempt from cross-examination volunteered testimony or
answers to open-ended questions than they were to exempt answers to
detailed interrogation.”). We believe it is unnecessary to decide whether
Inspector Agster’s interaction with the post office supervisor was an
“interrogation” because we conclude that the primary purpose of the
interaction was investigative, regardless of how the interaction is labeled.
12               UNITED STATES V. BROOKS

purpose of creating an out-of-court substitute for trial
testimony.” Michigan v. Bryant, 131 S. Ct. 1143, 1155
(2011). In making this determination, the goal is not to
discern “the subjective or actual purpose of the individuals
involved in a particular encounter, but rather the purpose that
reasonable participants would have had, as ascertained from
the individuals’ statements and actions and the circumstances
in which the encounter occurred.” Id. at 1156.

    Davis and Hammon guide our inquiry. The events in
Davis began with a call to a 911 operator that terminated
before anyone spoke, prompting the operator to return the
call. 547 U.S. at 817. Michelle McCottry answered, and
when the operator asked her what was going on, she said,
“He’s here jumpin’ on me again. . . . He’s usin’ his fists.” Id.
As the conversation continued, McCottry reported that her
former boyfriend had just run out the door after hitting her.
Id. at 818. The operator then gathered information about the
former boyfriend, and McCottry described the assault. Id.
McCottry did not appear at the subsequent trial, but the state
introduced the 911 tape. Id. at 819.

    In Hammon, police responded to a reported domestic
dispute at the home of Amy and Hershel Hammon. Id. The
officers found Amy “alone on the front porch, appearing
somewhat frightened, but she told them that nothing was the
matter.” Id. (internal quotation marks omitted). One officer
dealt with Hershel, insisting that he stay separated from Amy
to allow the officers to investigate what happened. Id. at
819–20. In another room, the other officer questioned Amy
about what had occurred and, after listening to her account,
asked her to complete a battery affidavit. Id. She wrote:
“Broke our Furnace & shoved me down on the floor into the
broken glass. Hit me in the chest and threw me down.” Id.
                UNITED STATES V. BROOKS                    13

at 820 (internal quotation marks omitted). Amy did not
appear at Hershel’s trial, but the police officers testified
regarding her statements and authenticated the affidavit. Id.
at 820–21.

    The Court held that the statements in Hammon were
testimonial and that the statements in Davis were not. “[T]he
nature of what was asked and answered in Davis,” the Court
explained, “was such that the elicited statements were
necessary to be able to resolve the present emergency, rather
than simply to learn . . . what had happened in the past.” Id.
at 827. For example, the operator’s attempt to establish the
assailant’s identity was needed “so that the dispatched
officers might know whether they would be encountering a
violent felon.” Id. The informality of the call, in which the
victim’s “frantic answers were provided . . . in an
environment that was not tranquil, or even . . . safe,” also
contributed to the conclusion that the statements were not
testimonial. Id.

    By contrast, in Hammon there was no “immediate threat”
to the speaker, and law enforcement “was not seeking to
determine (as in Davis) ‘what is happening,’ but rather ‘what
happened.’” Id. at 830. “It was formal enough that Amy’s
interrogation was conducted in a separate room, away from
her husband (who tried to intervene), with the officer
receiving her replies for use in his investigation.” Id.
(internal quotation marks and brackets omitted). Amy’s
statements in response to police questioning were “an obvious
substitute for live testimony, because they d[id] precisely
what a witness does on direct examination.” Id.

   Davis and Hammon lead us to conclude that the postal
supervisor’s statements here were testimonial. First, based on
14              UNITED STATES V. BROOKS

the content and context of the conversation, a reasonable
person would have understood the primary purpose to be
investigative. Postal employees presumably would have
known Inspector Agster to be a law enforcement officer, so
when he called to ask whether someone matching a certain
description was present, the most reasonable assumption
would have been that the inquiry related to a criminal
investigation. But even if that were not obvious at the
outset—for example, perhaps one could have thought that the
suspect was carrying a bomb and the call was intended to
address that emergency—the investigative purpose would
have become clear once the discussion turned to the details of
the package’s mailing information rather than, say,
evacuation of the building. Thus, as the call proceeded, both
participants would have known that the primary purpose of
the conversation was to establish or prove facts potentially
relevant to a later criminal prosecution. By working with
Agster to gather incriminating evidence about the suspect, the
supervisor became part of the effort to collect information
necessary to make out a case against the suspect.

    Second, Agster’s interaction with the supervisor was
somewhat formal. Unlike Davis, in which the contested
statements were made to a 911 operator, here, as in Hammon,
the conversation involved a bona fide law enforcement
officer. Testimony must be solemn, and the Supreme Court
has explained that the solemnity of oral statements to law
enforcement is established “by the severe consequences that
can attend a deliberate falsehood.” Davis, 547 U.S. at 826
(explaining that false statements to federal investigators
violate 18 U.S.C. § 1001); see also United States v. McKanry,
628 F.3d 1010, 1018 (8th Cir. 2011) (affirming a conviction
under 18 U.S.C. § 1001 for a false statement to a postal
inspector). Additionally, in contrast to McCottry’s frantic
                 UNITED STATES V. BROOKS                    15

answers in Davis, here there is no indication that Agster’s
phone conversation was rushed. Although confirming the
suspect’s presence in the post office may have been time-
sensitive, collecting a specific description of the parcel was
not. Rather, the circumstances suggest that the pace and
deliberateness of the phone call were much more similar to
the interrogation in Hammon than to the 911 call in Davis.

    Third, as in Hammon, the supervisor’s statements
reported “what happened”—that is, that the man in the blue
shirt mailed a package bearing certain identifying
information—rather than “what is happening.” 547 U.S. at
830 (internal quotation marks omitted). Although the
suspect’s presence was confirmed in real time, there is no
indication that the supervisor relayed the package’s mailing
information while the suspect was still at the counter mailing
it. Rather, given the surrounding circumstances, we must
assume that the supervisor set aside the parcel and provided
the mailing information to Agster after the suspect left the
post office. The supervisor’s statements identifying a
particular package as the one mailed by the man in the blue
shirt were “an obvious substitute for live testimony” because
they did “precisely what a witness does on direct
examination.” Id. Whereas the statements in Davis were
nontestimonial partly because “[n]o ‘witness’ goes into court
to proclaim an emergency and seek help,” id. at 828,
witnesses routinely do go into court to say that they observed
a crime and collected evidence of it.

     Finally, our conclusion that the primary purpose was
investigative is reinforced by the lack of an alternative. That
is, if the purpose of Agster’s call was not to build a case for
prosecution, then what was the purpose? The government
does not suggest there was any sort of emergency, nor does
16                  UNITED STATES V. BROOKS

it say that Agster was trying to stop the suspect from getting
away.2 And although Agster may have wanted to prevent the
package from reaching its destination, that goal was realized
once the box was set aside. Collecting the tracking number
and mailing information, and then using that information to
select the parcel to be searched, was plainly done with an eye
toward prosecution.

      3. The statements were offered for their truth.

    In addition to being testimonial, the supervisor’s
statements were offered for their truth. The government
seems to suggest that the statements were offered solely to
provide foundation for the admission of photographs
depicting the search of the parcel, and not for their truth.
Foundational evidence is valuable, however, only if it is true.
In this respect, foundation differs from other situations in
which the truth of the statement is irrelevant, such as when
offered to show its effect on the listener. Here, the
prosecution was far from indifferent as to the truth of the
supervisor’s statements. The prosecution already had offered
evidence to prove that Brooks was the man in the blue shirt.
It wanted the jury to believe the supervisor correctly
identified the package mailed by the man in the blue shirt so
that it could connect the marijuana found in that package to
Brooks.

                              *     *    *


  2
    The lack of emergency distinguishes this case from United States v.
Solorio, 669 F.3d 943, 952–54 (9th Cir. 2012), and United States v. Liera-
Morales, 759 F.3d 1105, 1109–11 (9th Cir. 2014), in which we held that
statements were nontestimonial because they were offered to help resolve
dangerous situations.
                    UNITED STATES V. BROOKS                            17

    To summarize, we conclude that the prosecution
introduced statements by the postal supervisor that were
testimonial and offered for their truth. Because the postal
supervisor did not testify, and there is no contention of
unavailability or that Brooks had a prior opportunity to cross-
examine the supervisor, the admission of the statements
violated the Confrontation Clause.3

                         III. Harmlessness

    Once a Confrontation Clause error has been shown, the
government bears the burden of proving that it was harmless
beyond a reasonable doubt. United States v. Nguyen,
565 F.3d 668, 675 (9th Cir. 2009). The government’s
answering brief, despite noting that a harmlessness analysis
applies to Confrontation Clause violations, does not argue
that any error here was harmless. This constitutes waiver.
See United States v. Gonzalez-Flores, 418 F.3d 1093, 1100
n.4 (9th Cir. 2005) (“Although the government mentions that
a harmless error analysis applies, it makes no argument on
this score nor advances any theory about how any errors here
were harmless. Issues raised in a brief which are not
supported by argument are deemed abandoned.” (internal
quotation marks omitted)).

   In Gonzalez-Flores, we held that we have discretion to
consider harmlessness sua sponte in extraordinary cases, and

  3
    Setting aside the challenged testimony does not affect whether it was
proper to admit the photographs. Agster testified that he went to the post
office following his conversation with Officer Kinsey, that he took
pictures while searching the parcel, and that the photographs admitted at
trial were the ones that he took. Relevance and authenticity were therefore
established without the challenged testimony. See Fed. R. Evid. 401,
901(a).
18                   UNITED STATES V. BROOKS

that we should consider three factors to identify such cases:
(1) “the length and complexity of the record,” (2) “whether
the harmlessness of an error is certain or debatable,” and
(3) “the futility and costliness of reversal and further
litigation.” Id. at 1101. “[T]he second factor—the court’s
certainty as to the harmlessness of the error—is of particular
importance,” and sua sponte recognition “is appropriate only
where the harmlessness of the error is not reasonably
debatable.” Id.

    Unlike Gonzalez-Flores, this case involves constitutional
error. The burden to establish harmlessness is heavier for
constitutional errors than it is for non-constitutional errors.
Compare United States v. Sandoval-Gonzalez, 642 F.3d 717,
725 (9th Cir. 2011) (government must show it is more
probable than not that a non-constitutional error did not
materially affect the verdict), with Chapman v. California,
386 U.S. 18, 24 (1967) (government must show beyond a
reasonable doubt that a constitutional error did not contribute
to the verdict obtained). Thus, exercising our discretion to
find a constitutional error harmless under Gonzalez-Flores
requires a double level of certainty: we must be convinced
that the error was “harmless beyond a reasonable doubt” and
that “satisfaction of that standard is beyond serious debate.”
United States v. Pryce, 938 F.2d 1343, 1347–50 (D.C. Cir.
1991) (opinion of Williams, J., announcing the judgment)
(internal quotation marks and emphasis omitted).4


 4
   In addition to the D.C. Circuit, other circuits that share our standard for
when to recognize harmlessness sua sponte apply that standard to
constitutional errors. See, e.g., United States v. Torrez-Ortega, 184 F.3d
1128, 1135-37 (10th Cir. 1999) (considering harmlessness of
constitutional error notwithstanding government’s waiver); United States
v. Parmelee, 42 F.3d 387, 392 n.6 (7th Cir. 1994) (same).
                    UNITED STATES V. BROOKS                           19

    Even under this high standard, we find that the Gonzalez-
Flores factors favor exercising our discretion to determine
that admitting the postal supervisor’s out-of-court statements
was harmless as to two of Brooks’s three convictions—
possession with intent to distribute on November 17 (the day
of arrest) and conspiracy. First, the complexity of the record
is modest—the result of a four-day trial. Second, even
without the supervisor’s out-of-court statements—or even any
evidence at all regarding the mailing on November 9—there
was overwhelming evidence that Brooks participated in the
conspiracy and, on November 17, possessed marijuana with
intent to distribute.5 Among other things, Brooks lived with
the conspiracy leader in the Glendale apartment for at least a
month prior to his arrest, and the conspiracy leader referred
to Brooks as his “worker.” For several months, law
enforcement had observed cars travelling from the Glendale
apartment to post offices in order to ship marijuana, and a
search of the apartment revealed packaging materials and
numerous postal receipts. Brooks was responsible for a
handgun found at the Phoenix apartment and the silver Buick
used in the conspiracy, and he possessed almost two thousand
dollars in cash at the time of his arrest. Brooks was
apprehended at the Phoenix apartment, where bales of
marijuana were found on the kitchen counter, along with
more than a dozen mailing receipts and two sealed boxes with


   5
     Brooks also raises a Confrontation Clause challenge to evidence
suggesting that he mailed additional packages at a second post office on
November 9. Because no parcel was ever searched at the second post
office, there was no direct evidence that any marijuana was mailed at that
post office, even if the mailer was Brooks. We therefore conclude that the
evidence related to the second post office was of such minimal probative
value that its presence or absence has no effect on our evaluation of
Brooks’s convictions, and any error with respect to that evidence was
harmless.
20                  UNITED STATES V. BROOKS

marijuana ready for shipment. Third and finally, in light of
the overwhelming evidence, remand for retrial on the
conspiracy and November 17 possession counts would be
futile and costly. With all three Gonzalez-Flores factors
pointing in favor of sua sponte recognition, we exercise our
discretion to overlook the government’s waiver and hold the
Confrontation Clause error harmless with respect to the
convictions on those two counts.

    Our harmlessness conclusion is different, however, with
respect to the conviction for possession with intent to
distribute on November 9.6 Certainty as to harmlessness is a
prerequisite for sua sponte recognition under Gonzalez-
Flores. The government acknowledged at oral argument that
any Confrontation Clause error would not have been clearly
harmless as to the November 9 count. We agree. The
prosecution offered substantial evidence to prove that Brooks
was the man in the blue shirt who entered the post office with
a box, but the supervisor’s improperly admitted statements
were the key evidence linking the man in the blue shirt to the
seized parcel and the marijuana it contained. Absent those

 6
   In light of Brooks’s longer, concurrent prison sentence for conspiracy,
the government argues that reversal of the November 9 conviction will not
reduce the amount of time he serves. Even if that is true, it does not
render reversal unnecessary because the conviction carries a special
assessment of $100. 18 U.S.C. § 3013(a)(2)(A); see Ray v. United States,
481 U.S. 736, 736–37 (1987) (per curiam) (holding that review of each
conviction was required despite the defendant’s concurrent prison terms
because each conviction carried a $50 assessment). And even without the
special assessment, we still could not decline review. See United States
v. DeBright, 730 F.2d 1255, 1258–60 (9th Cir. 1984) (en banc)
(overturning the concurrent sentence doctrine, under which we formerly
had authority to decline consideration of an alleged error impacting one
count on the ground that an equally long or longer concurrent prison
sentence had been imposed on another count).
                    UNITED STATES V. BROOKS                            21

statements, we cannot say with certainty that the jury would
have reached the same verdict, particularly given that certain
evidence at trial supported the possibility that Brooks mailed
something other than marijuana. We thus decline to find the
Confrontation Clause violation harmless as to the November
9 count.7

                      IV. Other Contentions

    In addition to the Confrontation Clause issue, Brooks
argues that the district court erred by denying his motion to
suppress evidence obtained via warrantless GPS monitoring
and his request for a minor participant adjustment at
sentencing. These arguments can be dealt with summarily.

    Brooks’s contention regarding GPS monitoring is
foreclosed by United States v. Pineda-Moreno, 688 F.3d
1087, 1090–91 (9th Cir. 2012), in which we held that the
exclusionary rule does not apply to evidence obtained from
a GPS device placed on a suspect’s car prior to United States
v. Jones, 132 S. Ct. 945 (2012).

    Brooks is also mistaken that the district court abused its
discretion by denying him a minor participant adjustment at
sentencing. Brooks did not show that he was substantially
less culpable than his co-conspirators. See United States v.
Cantrell, 433 F.3d 1269, 1282–83 (9th Cir. 2006). Ample


  7
   We leave it for the district court to determine in the first instance on
remand whether Brooks’s sentence for the remaining convictions should
be adjusted. Because the district court may consider on remand any
sentencing arguments it finds appropriate, we dismiss as moot Brooks’s
motion to remand based on changes to the United States Sentencing
Guidelines.
22               UNITED STATES V. BROOKS

evidence supported the district court’s conclusion that Brooks
was deeply embedded in the conspiracy.

                       V. Conclusion

    For the reasons discussed above, we hold that admission
of the postal supervisor’s out-of-court statements violated the
Confrontation Clause. Although we exercise our discretion
to overlook the government’s waiver and hold the error
harmless as to two of Brooks’s convictions, we decline to do
so with respect to his conviction for possession with intent to
distribute on November 9, 2011. Accordingly, we AFFIRM
Brooks’s convictions for possession with intent to distribute
on November 17 and conspiracy, REVERSE his conviction
for possession with intent to distribute on November 9, and
REMAND to the district court to determine whether
resentencing is appropriate.
