In the

    United States Court of Appeals
                For the Seventh Circuit
                    ____________________
No. 14-2236
UNITED STATES OF AMERICA,
                                                  Plaintiff-Appellee,

                                v.

DAVID LEWISBEY,
                                              Defendant-Appellant.
                    ____________________

        Appeal from the United States District Court for the
          Northern District of Illinois, Eastern Division.
           No. 12-cr-354 — Ronald A. Guzmán, Judge.
                    ____________________

 ARGUED NOVEMBER 13, 2015 — DECIDED DECEMBER 9, 2016
                    ____________________

   Before POSNER, RIPPLE, and SYKES, Circuit Judges.
    SYKES, Circuit Judge. David Lewisbey was a Chicago-
based gunrunner who used a fake Indiana I.D. to buy guns
at Indiana gun shows and bring them back to Illinois to sell.
He came to the attention of law enforcement when he
bragged about his gunrunning exploits on Facebook. Federal
agents set up a sting, and Lewisbey was arrested and
charged with multiple counts of unlawfully transporting
and dealing firearms. A jury convicted him on all counts.
2                                                 No. 14-2236

   Lewisbey now argues that his attorney was operating
under a conflict of interest in violation of his Sixth Amend-
ment right to conflict-free counsel. He also challenges the
admission of incriminating text-message and Facebook
evidence at trial. Finally, he claims that the testimony of the
government’s cell-phone location expert did not satisfy the
requirements of Daubert v. Merrill Dow Pharmaceuticals, Inc.,

(1993). We reject these arguments and affirm.
                       I. Background
    David “Big Dave” Lewisbey conducted a thriving inter-
state gunrunning business from his home in Chicago. He
purchased guns at Indiana gun shows with a fake Indiana
I.D. and then sold them in Illinois. Federal authorities
learned of these activities when Lewisbey boasted about
them on his Facebook page; an undercover operation was
commenced. After Lewisbey sold a total of 43 guns to a
confidential informant in five separate controlled purchases,
law enforcement moved in and arrested him. He was
charged with one count of unlawful dealing in firearms
without a license, 18 U.S.C. § 922(a)(1)(A); two counts of
illegally transporting firearms across state lines, 

924(a)(1)(D); and two counts of traveling across
state lines with intent to engage in the unlicensed dealing of
firearms, 

   Lewisbey’s defense at trial was that he was a gun collec-
tor rather than a gunrunner. The evidence showed other-
wise. The prosecution’s case included video recordings of
Lewisbey’s sales to the confidential informant, text messages
showing that Lewisbey habitually sold guns to purchasers
other than the confidential informant, and Facebook photos
depicting Lewisbey with lots of guns and large sums of
No. 14-2236                                                  3

money. Michael Hall, a business contact of Lewisbey’s who
occasionally acted as his go-between, testified to the details
of some transactions. Another witness testified about selling
guns to Lewisbey in a McDonald’s parking lot in Indiana.
Multiple witnesses testified that they knew Lewisbey from
Indiana gun shows and knew that he used a fake Indiana
I.D. to illegally purchase guns. Finally, FBI Special Agent
Joseph Raschke testified, based on his analysis of Lewisbey’s
phone records, that calls were made from Lewisbey’s phones
at times and locations consistent with the illegal gun transac-
tions described by other witnesses. A jury returned a verdict
of guilty on all counts, and the judge sentenced Lewisbey to
200 months in prison.
     Lewisbey was represented in the district court by Attor-
ney Beau Brindley. At the time Brindley was himself facing a
criminal contempt proceeding in the Central District of
Illinois. When questioned by the judge about the potential
conflict of interest, Lewisbey expressly waived any conflict
and consented to Brindley’s continuation as his counsel.
Following the entry of judgment, and soon after this appeal
was filed, the government sought a limited remand to
address a different conflict of interest stemming from a new
federal criminal investigation targeting Brindley. We re-
manded the case so the district judge could determine
whether a conflict of interest existed and obtain a waiver if
necessary. Brindley promptly withdrew and another attor-
ney took over Lewisbey’s appeal. With a new attorney in
place, the judge canceled the conflict hearing and the appeal
resumed.
4                                                   No. 14-2236

                        II. Discussion
    Lewisbey raises two arguments on appeal. First, he con-
tends that Brindley’s troubles with law enforcement created
an unconstitutional conflict of interest in violation of his
Sixth Amendment right to conflict-free counsel. Second, he
challenges the admission of his text messages, Facebook
posts, and the testimony of Special Agent Raschke, the
government’s cell-phone location expert.
A. Sixth Amendment Right to Conflict-Free Counsel
    Because the Sixth Amendment protects the right to coun-
sel “whose undivided loyalties lie with the client,” a defend-
ant whose trial attorney was “burdened by a conflict of
interest” may be entitled to a new trial. United States v.
Barnes, 

, 1065 (7th Cir. 1990) (quotation marks
omitted) (citing Cuyler v. Sullivan, 

(1980)).
Conflicts of interest in this context usually arise in cases
involving joint representation, but a conflict may also arise
“when a client’s interest conflicts with that of his attorney.”
United States v. Ellison, 

, 1106–07 (7th Cir. 1986).
    Lewisbey argues that Brindley’s interests conflicted with
his own because Brindley was the subject of not one but two
criminal investigations, giving him an incentive to curry
favor with the government. To establish a violation of the
Sixth Amendment right to conflict-free counsel, the defend-
ant “must demonstrate that an actual conflict of interest
adversely affected his lawyer’s performance.” 

. The mere possibility of a conflict is “insuffi-
cient to impugn a criminal conviction.” 

   Because Lewisbey affirmatively waived any conflict aris-
ing from Brindley’s contempt proceeding, see United States v.
No. 14-2236                                                   5

Lowry, 

, 61 (7th Cir. 1992), his Sixth Amendment
claim can only relate to the second criminal investigation
against Brindley. But that investigation came to light after
Lewisbey was convicted and sentenced and his case had
already moved to this court. When Brindley learned that he
was the subject of this second investigation, he immediately
withdrew; a new, conflict-free attorney thereafter assumed
responsibility for the appeal. Brindley’s withdrawal cured
the potential conflict, removing any possible Sixth Amend-
ment concern.
B. Evidentiary Rulings
   1. Text Messages and Facebook Posts
    Over Lewisbey’s objection the judge allowed the gov-
ernment to introduce certain inculpatory text messages from
Lewisbey’s phones and posts from his Facebook page. We
review evidentiary rulings deferentially, for abuse of discre-
tion only. United States v. Schmitt, 

, 532 (7th Cir.
2014), cert. denied, 

(2015). “[W]e will defer to
the district court unless no reasonable person could adopt its
view. Even then, reversal only follows if admission of the
evidence affected the defendant’s substantial rights.” 

quotation marks omitted).
    Lewisbey argues that the Facebook posts and the text
messages taken from two phones—a Samsung and an
iPhone—should have been excluded on both hearsay and
authentication grounds. See FED. R. EVID. 801, 901. He also
argues that the prejudicial impact of this evidence substan-
tially outweighs its limited probative value and thus the
evidence should have been excluded under Rule 403 of the
Federal Rules of Evidence.
6                                                 No. 14-2236

    The hearsay objection is a nonstarter. The text messages
Lewisbey sent are his own statements and as such are ex-
cluded from the definition of hearsay by Rule 801(d)(2)(A).
The messages he received were admitted not for the truth of
the matter asserted but instead to provide context for
Lewisbey’s own messages See FED. R. EVID. 801(c)(2); United
States v. Robinzine, 

, 252 (7th Cir. 1996) (State-
ments offered not to prove “the truth of the matter asserted”
but for another legitimate purpose do “not even fit the
definition of hearsay.”). And Lewisbey admitted that the
Facebook posts were his, so like his “sent” text messages, the
posts    qualify    as   nonhearsay      admissions    under
Rule 801(d)(2).
    The authentication objection fares no better. To authenti-
cate the text messages, the government needed only to
“produce evidence sufficient to support a finding” that the
messages were actually sent and received by Lewisbey. FED.
R. EVID. 901(a). The government clearly did so. The iPhone
was confiscated from Lewisbey at the time of his arrest, and
in a recorded phone call from the jail, he told his mother that
the police took his phone. The Samsung device was recov-
ered from his bedroom at his parents’ home, a room that
both parents identified as belonging exclusively to him. The
“Properties” section of the iPhone described the phone as
“Big Dave’s,” and the contacts directory included infor-
mation for Lewisbey’s mother listed under the heading
“Mom,” and also the name and number of his former attor-
ney. Both phones listed contact information for the Texas
Home Depot stores where Lewisbey used to work. And the
confidential informant arranged gun sales with Lewisbey on
the Samsung phone. That’s more than enough to establish
that the two phones were indeed Lewisbey’s. See FED. R.
No. 14-2236                                                 7

EVID. 901(b)(4) (“The appearance, contents, substance,
internal patterns, or other distinctive characteristics of the
item, taken together with all the circumstances,” can estab-
lish that “the item is what the proponent claims it is.”).
     Lewisbey’s admission that the Facebook posts were his is
enough for authentication, but if more were needed, the
Facebook page lists Lewisbey’s nickname, his date of birth,
and his place of residence (Houston) where he lived prior to
Illinois. The email addresses associated with the Facebook
account correspond to both the email linked with Lewisbey’s
iPhone and his former email address at the University of
Kansas. The Facebook page contains more than 100 photos
of Lewisbey—including a profile picture—and many of the
Facebook photos match photos also found on Lewisbey’s
iPhone. The Facebook application on Lewisbey’s iPhone was
linked to this Facebook account. And messages on the
account discuss Lewisbey’s trips to gun shows in Fort
Wayne and Indianapolis on dates when gun shows actually
occurred at these locations.
    Finally, Lewisbey argues that the text messages and
Facebook posts should have been excluded under Rule 403
because they were merely cumulative. This argument is
frivolous. The text messages and Facebook posts were
corroborative, not cumulative. Recall that Lewisbey’s de-
fense at trial was that he was just a gun collector. The text
messages and Facebook posts were admitted to rebut this
defense by corroborating the witnesses who testified about
Lewisbey’s gunrunning activities. The evidence was neither
needlessly cumulative nor unfairly prejudicial and was
properly admitted.
8                                                    No. 14-2236

    2. Cell-Phone Expert Testimony
    Finally, Lewisbey challenges the judge’s decision to allow
Special Agent Raschke to testify about Lewisbey’s phone
records. Agent Raschke explained that Lewisbey’s phone
records showed calls made at places and times that corre-
sponded to the testimony of the other prosecution witnesses.
Lewisbey claims that this testimony did not meet the re-
quirements of expert testimony under Rule 702 of the Feder-
al Rules of Evidence, which requires that
           (a) the expert’s scientific, technical, or other
       specialized knowledge will help the trier of
       fact to understand the evidence or to determine
       a fact in issue;
          (b) the testimony is based on sufficient facts
       or data;
          (c) the testimony is the product of reliable
       principles and methods; and
           (d) the expert has reliably applied the prin-
       ciples and methods to the facts of the case.
    Under the familiar framework established in Daubert, the
district judge consults a nonexhaustive list of factors to
determine whether the requirements of Rule 702 are met;
these include: (1) whether the expert’s technique or theory is
testable or has been tested; (2) whether the technique or
theory has been subject to peer review and publication;
(3) the known or potential rate of error in applying the
technique or theory; (4) whether standards and controls exist
and were maintained; and (5) whether the technique or
theory is generally accepted in the scientific 

–94. The court’s gatekeeping function applies
No. 14-2236                                                  9

to all expert testimony and not just scientific expert testimo-
ny. Kumho Tire Co. v. Carmichael, 

, 147–49 (1999).
On appeal we ask first whether the judge applied the proper
framework. C.W. ex rel. Wood v. Textron, Inc., 

,
835 (7th Cir. 2015). If the judge did so, then we review the
decision to admit the expert’s testimony for abuse of discre-
tion. 

reflects that the judge conducted a thorough
Daubert analysis of Agent Raschke’s proposed testimony and
soundly exercised his discretion to admit it. Using call
records and cell towers to determine the general location of a
phone at specific times is a well-accepted, reliable methodol-
ogy. See, e.g., Rick Ayers, Sam Brothers & Wayne Jansen,
Nat’l Inst. of Standards & Tech., Guidelines on Mobile Device
Forensics, § 6.3 at 54 (2014), http://nvlpubs.nist.gov/
nistpubs/SpecialPublications/NIST.SP.800-101r1.pdf (“Call
detail records can also be used with cell site tower infor-
mation obtained from the service provider to translate cell
identifiers into geographic locations for the cells involved
and identify the general locale from which calls were
placed.”); United States v. Jones, 

, 5 (D.D.C.
2013) (“[T]he use of cell phone location records to determine
the general location of a cell phone has been widely accepted
by numerous federal courts.”). With 350 hours of training in
the systems used by the relevant network service providers,
Agent Raschke had ample expertise in this methodology.
And the judge also appropriately recognized the limits of
this technique by barring the agent from couching his testi-
mony in terms that would suggest that he could pinpoint the
exact location of Lewisbey’s phones. We find no abuse of
discretion.
10                                               No. 14-2236

    We note in closing that no evidentiary error requires re-
versal unless it affected the defendant’s substantial rights;
this in turn requires that “the average juror would have
found the prosecution’s case significantly less persuasive
absent the erroneous evidentiary ruling.” United States v.
Trudeau, 

, 590 (7th Cir. 2016). The record con-
tains prodigious evidence of Lewisbey’s guilt. We’re confi-
dent that none of the claimed evidentiary errors—if indeed
they were errors—had a significant effect on the jury’s
verdict.
                                                  AFFIRMED.