                           PUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


UNITED STATES OF AMERICA,              
                 Plaintiff-Appellee,
                 v.                              No. 01-4335
WILLIAM LEE PATTERSON,
              Defendant-Appellant.
                                       
           Appeal from the United States District Court
          for the Eastern District of Virginia, at Norfolk.
             Robert G. Doumar, Senior District Judge.
                           (CR-00-187)

                      Argued: December 6, 2001

                      Decided: January 18, 2002

      Before WILKINS and WILLIAMS, Circuit Judges, and
              HAMILTON, Senior Circuit Judge.



Affirmed by published opinion. Judge Wilkins wrote the opinion, in
which Judge Williams and Senior Judge Hamilton joined.


                             COUNSEL

ARGUED: Douglas Fredericks, Norfolk, Virginia, for Appellant.
Laura Marie Everhart, Assistant United States Attorney, Norfolk, Vir-
ginia, for Appellee. ON BRIEF: Kenneth E. Melson, United States
Attorney, Norfolk, Virginia, for Appellee.
2                     UNITED STATES v. PATTERSON
                               OPINION

WILKINS, Circuit Judge:

   Appellant William Lee Patterson was convicted of possession with
the intent to distribute cocaine base, see 21 U.S.C.A. § 841(a)(1)
(West 1999), and aiding and abetting possession with the intent to dis-
tribute cocaine base, see 18 U.S.C.A. § 2(a) (West 2000). He con-
tends that the district court erred by (i) refusing to dismiss the charges
for lack of a speedy trial and (ii) admitting laser-generated images of
his fingerprints. We affirm.

                                    I.

   We first address Patterson’s claim that the district court erred in
denying his motion to dismiss this case pursuant to the Speedy Trial
Act (STA) of 1974, see 18 U.S.C.A. §§ 3161-3174 (West 2000). The
STA imposes a 70-day deadline for commencing trial. See id.
§ 3161(c)(1). Certain periods are excluded from STA computations,
however. As is relevant here, excludable periods include "[a]ny
period of delay resulting from the absence or unavailability of . . . an
essential witness," id. § 3161(h)(3)(A), and "[a]ny period of delay
resulting from a continuance granted . . . on the basis . . . that the ends
of justice served by taking such action outweigh the best interest of
the public and the defendant in a speedy trial," id. § 3161(h)(8)(A).
There are no facts in dispute, so we review the application of these
provisions de novo. See United States v. Jarrell, 147 F.3d 315, 317
(4th Cir. 1998).

   Patterson contends that the district court erred by granting a contin-
uance on December 29, 2000 to enable the Government to secure the
attendance of a witness named Jermaine Green. At the time, trial was
scheduled to begin on January 4, 2001, near the end of the 70-day
period. The December 29 continuance postponed the trial until Febru-
ary 1, 2001.

   According to the undisputed evidence presented at the hearing on
the Government’s motion, the Government properly subpoenaed
Green for Patterson’s trial. Shortly before the trial was scheduled to
                      UNITED STATES v. PATTERSON                        3
begin, however, Green was arrested in South Carolina on charges of
homicide and assault with intent to kill. Deputy Marshal Nicholas
Proffitt testified that the United States Marshals Service (USMS)
could bring Green to Norfolk, Virginia in time for trial but that doing
so would require chartering a plane or driving to South Carolina,
because the charges against Green would preclude the use of commer-
cial air travel. Moreover, having to dispatch personnel for this pur-
pose would create "a hardship" for the USMS. J.A. 21.

   Another obstacle to retrieving Green in time for trial was that
Green had a hearing scheduled in state court in South Carolina on
January 8, 2001. While the district court had the power to compel
Green’s custodians to surrender him to the USMS, the court found
that it was unlikely that a writ of habeas corpus ad testificandum
could even be served before January 2, 2001 (the next business day
after the hearing). There was also speculation that South Carolina
might refuse to comply with the writ in light of Green’s imminent
hearing concerning the very serious charges he was facing; the Gov-
ernment did not contact any South Carolina officials to inquire about
this, however, and the district court did not mention this possibility
when it granted the continuance.

   Acting through a duty judge, the district court noted two grounds
for granting a continuance. First, the court ruled that "as a practical
matter [Green] is unavailable." Id. at 22. Second, the court found that
"the interests of the defendant and the public in a speedy trial [are]
outweighed by the ends of justice in requiring a continuance." Id. at
23. We hold that the continuance was proper for both of the reasons
stated.1

   Patterson concedes that Green was an essential witness but con-
tends that § 3161(h)(3)(A) is nonetheless inapplicable because the
  1
   In light of our holding, we do not reach a related argument presented
by Patterson. Following trial, Patterson moved for judgment of acquittal
based on the alleged STA violation. The trial judge denied this motion
on the basis that the duty judge’s determination was the law of the case.
Because there was no STA violation, the denial of the motion for judg-
ment of acquittal was proper regardless of whether the trial judge’s anal-
ysis was correct.
4                     UNITED STATES v. PATTERSON
Government could have secured Green’s presence. He relies in partic-
ular on Marshal Proffitt’s statement to the court that the USMS
"would have [Green] here on the day you told us to have him here."
Id. at 21. This argument ignores the remainder of Proffitt’s testimony,
however. Proffitt advised the court—and Patterson does not dispute—
that transporting Green would impose a "hardship" on the USMS. Id.
Such exertion is not required by the STA; instead, a witness is consid-
ered unavailable for purposes of § 3161(h)(3)(A) if "his presence for
trial cannot be obtained by due diligence." 18 U.S.C.A.
§ 3161(h)(3)(B); see Wims v. United States, 225 F.3d 186, 190 n.4 (2d
Cir. 2000) (holding that a "due diligence" standard "does not require
the maximum feasible diligence, only ‘due,’ or reasonable, dili-
gence"). Because the undisputed facts demonstrate that Green’s pres-
ence could not be secured through reasonable efforts, the district court
did not err in granting a continuance.2

   In addition, the continuance was proper based on the determination
by the district court that postponing the trial served the interests of
justice to an extent that outweighed conflicting interests in a speedy
trial. In this regard, it is significant that removing Green from South
Carolina would have interfered with a state prosecution there. See
United States v. Lopez-Espindola, 632 F.2d 107, 111 (9th Cir. 1980)
(stating that courts generally should not apply the STA in a manner
that results in disruption of state criminal proceedings). Furthermore,
as noted by the district court at the December 29 hearing, Patterson
did not allege that any prejudice would result from the requested con-
tinuance. For these reasons, the December 29 continuance was proper
under § 3161(h)(8) as well as § 3161(h)(3).

                                    II.

    Patterson’s second claim is that the district court erred in allowing
    2
    Patterson contends that the Government did not act diligently because
it did not request a writ of habeas corpus or inquire whether Green’s cus-
todians would comply with such a writ. At most, this argument suggests
that the Government might have been able to acquire custody of Green;
it does not negate the fact that the USMS could not have transported
Green to Norfolk in time for the original trial date without hardship.
                     UNITED STATES v. PATTERSON                        5
the Government to introduce certain fingerprint evidence. We hold
that there was no reversible error.

   After Patterson was arrested, a sheriff’s deputy used a Digital Bio-
metrics Tenprinter to produce an image of Patterson’s fingerprints. At
trial, the deputy explained that this device is

    sort of like a laser scanner. The easiest way I could say, to
    give you a general idea about it, would be like going to the
    supermarket . . . where they scan your bar code for prices,
    it’s similar to that. It reads — it actually picks up the ridges
    on your fingers.

J.A. 29. The deputy admitted that this testimony was based on what
he had been told by others; although he used the Tenprinter every day
and had processed at least a thousand people with it, he did not know
how it worked. Furthermore, the accuracy of fingerprints recorded by
the Tenprinter had neither been confirmed nor challenged by any per-
son whose prints the deputy had processed.

   Patterson objected to this testimony regarding the Tenprinter and
to the admission of the fingerprint image produced by the machine
("the Tenprinter image"). The district court overruled these objec-
tions, holding that this evidence was admissible in light of the depu-
ty’s extensive experience operating the Tenprinter. Subsequently, an
expert witness testified that one of the prints on the Tenprinter image
matched a print recovered from a bag containing cocaine base that the
police discovered during their investigation of Patterson. No laser
device was used to locate or make a record of the fingerprint on the
bag.

   We hold initially that the admission of the deputy’s testimony
describing the operation of the Tenprinter was, at worst, harmless
error. The deputy’s lack of knowledge about the mechanism within
the Tenprinter and the accuracy of the fingerprint images it produced
undercut the probative value of his testimony regarding these issues.
Because this lack of knowledge was highlighted during defense coun-
sel’s skillful cross-examination, however, there is no likelihood that
the jury was misled into accepting testimony that the deputy was not
qualified to offer. See United States v. Williams, 81 F.3d 1321, 1326
6                     UNITED STATES v. PATTERSON
(4th Cir. 1996) (holding that error in admission of evidence is harm-
less if improper evidence did not substantially influence jury).

   As for the Tenprinter image, we hold that it was properly authenti-
cated. Under the Federal Rules of Evidence, "[t]he requirement of
authentication or identification as a condition precedent to admissibil-
ity is satisfied by evidence sufficient to support a finding that the mat-
ter in question is what the proponent claims." Fed. R. Evid. 901(a).
To meet the threshold established by Rule 901(a), the party seeking
to introduce physical evidence must provide "a basis for the jury to
resolve the authenticity question in favor of" that party. United States
v. Capers, 61 F.3d 1100, 1106 (4th Cir. 1995). We review decisions
of a district court regarding authentication for abuse of discretion. See
United States v. Patterson, 150 F.3d 382, 387 (4th Cir. 1998).

   Questions of authentication take many forms. See, e.g., United
States v. Siddiqui, 235 F.3d 1318, 1322-23 (11th Cir. 2000) (whether
e-mail message was authored by defendant), cert. denied, 121 S. Ct.
2573 (2001); United States v. Trujillo, 146 F.3d 838, 843-44 (11th
Cir. 1998) (whether paper identified by officer was same paper
removed from defendant’s mouth by different officer). The question
here is whether the Government offered sufficient evidence to demon-
strate that the Tenprinter image reliably depicted Patterson’s finger-
prints. Issues of this nature arise frequently in the context of
photographs, and we therefore look to cases involving the admission
of photographic evidence.

   The necessary foundation for the introduction of a photograph is
most commonly established through eyewitness testimony that the
picture accurately depicts the scene in question or expert testimony
that the picture was generated by a reliable imaging process. See
United States v. Rembert, 863 F.2d 1023, 1026 (D.C. Cir. 1988).
Here, there was no Government witness who had examined Patter-
son’s fingers and could verify that they were accurately rendered on
the Tenprinter image. Also, while the deputy who operated the Ten-
printer offered brief testimony about how it functioned, his lack of
expertise rendered his testimony insufficient to prove the reliability of
the device. Thus, the admission of the Tenprinter image was not sup-
ported by either of the most common evidentiary foundations. An
adequate foundation was provided, however, by "internal patterns[ ]
                     UNITED STATES v. PATTERSON                      7
or other distinctive characteristics, taken in conjunction with circum-
stances." Fed. R. Evid. 901(b)(4). Specifically, the testimony that one
of the fingerprints recorded by the Tenprinter matched the fingerprint
recovered from the drug container, if credited by the jury, provided
compelling evidence that the Tenprinter reliably imaged Patterson’s
fingers; the alternative—that the machine generated an inaccurate fin-
gerprint image that happened to be identical to a fingerprint recovered
by a different person using a different process in a different location
—is simply implausible. See People v. Webb, 862 P.2d 779, 798 (Cal.
1993) (en banc). Accordingly, the introduction of this evidence pro-
vides no basis for relief.

                                 III.

   For the foregoing reasons, the judgment of the district court is
affirmed.

                                                          AFFIRMED
