United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT
       ___________

       No. 02-2221
       ___________

United States of America,              *
                                       *
            Appellee,                  *
                                       *
      v.                               *
                                       *
Karl Kessler,                          *
                                       *
            Appellant.                 *

       ___________
                                           Appeals from the United States
       No. 02-2223                         District Court for the
       ___________                         Northern District of Iowa.

United States of America,              *
                                       *
            Appellee,                  *
                                       *
      v.                               *
                                       *
Adele Hylback,                         *
                                       *
            Appellant.                 *
                                  ___________

                             Submitted: December 11, 2002

                                 Filed: March 3, 2003
                                  ___________
Before WOLLMAN, HEANEY, and MELLOY, Circuit Judges.
                         ___________

WOLLMAN, Circuit Judge.


       A jury convicted Karl Kessler and Adele Hylback of conspiring to manufacture
five grams or more of methamphetamine in violation of 21 U.S.C. § 846. A jury also
convicted Hylback of aiding and abetting the manufacture of pure methamphetamine
in violation of 21 U.S.C. § 841(a)(1), and Kessler of possessing a firearm while being
a user of controlled substances in violation of 18 U.S.C. § 922(g)(3). The district
court1 sentenced Kessler to ninety-seven months in prison for the conspiracy charge,
to be served concurrently with a sentence of thirty-seven months for the firearm
charge, and Hylback to two concurrent fifty-one month sentences.

       Kessler and Hylback appeal, contending that the evidence presented was
insufficient to support their convictions. Kessler also contends that the district court
erred in enhancing his sentence for obstruction of justice. Hylback argues that the
district court erred in determining that the methamphetamine at issue was pure
methamphetamine and in calculating her base offense level under USSG §
2D1.1(a)(3). We affirm.

                      I. SUFFICIENCY OF THE EVIDENCE

       In considering a challenge to the sufficiency of the evidence supporting a guilty
verdict, we “look at the evidence in the light most favorable to the verdict and accept
as established all reasonable inferences supporting the verdict.” United States v.
Harmon, 

, 892 (8th Cir. 1999) (citation omitted). We will uphold the


      1
        The Honorable Mark W. Bennett, Chief Judge, United States District Court
for the Northern District of Iowa.

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conviction unless “no reasonable jury could have found the defendant guilty beyond
a reasonable doubt.” 

       Kessler, Hylback, and two other individuals, Darren Shave and Mary Smeby,
were indicted and charged with drug conspiracy and manufacturing violations.
Kessler was also indicted on a related weapons violation. Another conspirator,
Richard Stock, was arrested on state charges and subsequently committed suicide
while in custody. The charges against these individuals arose from their involvement
in a conspiracy to manufacture methamphetamine in Worth County, Iowa.

      A jury convicted Kessler and Hylback of conspiring to manufacture five grams
or more of methamphetamine in violation of 21 U.S.C. § 846. To convict Kessler and
Hylback, the government was required to prove that they knowingly agreed or
conspired to manufacture methamphetamine, an illegal act. United States v.
Crossland, 

, 913 (8th Cir. 2002) (citing United States v. Davidson, 

, 406 (8th Cir. 1999); United States v. Grego, 

, 704 (8th Cir.
1984)). A conspiracy may consist of a tacit or implicit understanding rather than an
explicit or express agreement. 

States v. Pintar, 

, 1275
(8th Cir. 1980)). The government, further, must have shown that Kessler and
Hylback exhibited “some element of cooperation beyond mere knowledge of the
existence of the conspiracy.” 

States v. Duckworth, 

,
1053 (8th Cir. 1991)).

        Kessler contends that his acquittal on two of the counts charged undermines
the credibility of the evidence proffered against him at trial. That “ the jury acquitted
[Kessler] on charges seemingly supported by his co-conspirator’s testimony does not
nullify the value of that testimony . . . .” United States v. Woods, 

, 730
(8th Cir. 2001). Young, a coconspirator, testified that she and Kessler helped Stock,
another coconspirator, manufacture methamphetamine. Miller, a third coconspirator,
testified that Kessler supported the conspiracy financially. “The credibility of the

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witnesses’ testimony was for the jury to determine . . . [,]” United States v. Miller,

, 912 (8th Cir. 2002) (citation omitted), and the jury found the witnesses’
testimony to be credible.

       Physical evidence introduced at trial also supported the jury’s verdict.
Extensive physical evidence was gathered by state and federal agents during searches
of Kessler’s, Hylback’s, and the Shave/Smelby residences in May 2000 and March
2001. During these searches, agents seized drug paraphernalia, residual
methamphetamine, firearms and ammunition, a police scanner, and the remains of
methamphetamine labs. This evidence indicates Kessler’s involvement in the
methamphetamine conspiracy. Our review of the record satisfies us that both the
physical and testimonial evidence introduced at trial supports the jury’s verdict on
this count.

      Hylback does not contest the jury’s finding that she is guilty of conspiring to
manufacture and manufacturing methamphetamine. She asserts, however, that the
evidence presented was insufficient for the jury to convict her of conspiring to
manufacture and aiding and abetting in the manufacture of five grams or more of pure
methamphetamine. She challenges the sufficiency of the evidence supporting her
conviction, contending that the methamphetamine in question was not pure.

       The district court considers the relative purity of methamphetamine, as found
by the jury, in determining the penalty to be imposed for its manufacture, distribution,
or dispensation. United States v. Beltran, 

, 1158-59 (8th Cir. 1997);
see 21 U.S.C. § 841(b). The government adduced evidence at trial, including the
testimony of criminalist Patricia Kahn of the Iowa Division of Criminal Investigation,
concerning the purity of the methamphetamine yielded by the lab. This evidence
affirmatively demonstrated that the methamphetamine that Hylback conspired to
manufacture and that she aided in and abetted the manufacture of constituted five



                                          -4-
grams or more of pure methamphetamine. After carefully reviewing the record, we
conclude that the evidence introduced at trial supports the jury’s verdict on this count.

                             II. SENTENCING ISSUES

       “We review the application of the guidelines . . . de novo and factual findings
for clear error.” United States v. Gomez, 

, 781 (8th Cir. 2001) (citations
omitted). Whether Kessler committed perjury and in so doing obstructed justice is
a factual finding, and thus we will reverse the district court’s imposition of a sentence
enhancement under USSG § 3C1.1 only upon a showing of clear error. United States
v. Esparza, 

, 1054 (8th Cir. 2002).

       “A witness commits perjury if he ‘gives false testimony concerning a material
matter with the wilful intent to provide false testimony, rather than as a result of
confusion, mistake, or faulty memory.’” United States v. Thomas, 

, 489
(8th Cir. 1996) (citations omitted). “The district court must review the evidence and
make [an] independent finding, by a preponderance of the evidence, of perjury in
order to impose a sentence enhancement for obstruction of justice.” 

affirmed a district court’s finding of perjury and subsequent application of sentence
enhancements for obstruction of justice where the perjured testimony directly
contravened testimony of other witnesses or was contradicted by physical evidence
taken from the scene of the crime. Id.; see also United States v. Titlbach, 

, 923-24 (8th Cir. 2002). As we held in United States v. Willis, 

(8th Cir. 1991), however, “[t]he adjustment cannot be given simply because a
defendant testifies in his own behalf and the jury disbelieves him. The district court
itself must find that the defendant committed perjury before making the upward
adjustment.” 

(citing United States v. Dyer, 

,
533 (8th Cir. 1990)); see also United States v. Farmer, 

(8th Cir. 2002).




                                          -5-
        The district court in effect made such a finding in this case. During his
testimony, Kessler denied using and manufacturing methamphetamine. The jury,
after having considered extensive physical and testimonial evidence that directly
linked Kessler to the conspiracy, found beyond a reasonable doubt that Kessler
conspired to manufacture methamphetamine. The district court stated, “[T]here was
plenty of evidence for the jury to find beyond a reasonable doubt [that] the defendant
was guilty. And I understand he continues to maintain his innocence, but I heard the
trial testimony, and I think [it constitutes] obstruction of justice.” Because the court
in effect made a specific finding of perjury and because the imposition of the sentence
enhancement for obstruction of justice does not constitute clear error, we affirm on
this issue.

       Hylback contends that the district court calculated her base offense level
incorrectly because the offenses for which she was convicted and sentenced did not
involve pure methamphetamine but rather a mixture thereof. The jury found beyond
a reasonable doubt that Hylback manufactured and aided in and abetted the
manufacture of more than five grams of pure methamphetamine. The district court
at sentencing held Hylback responsible for manufacturing at least thirty-two grams
of pure methamphetamine and assigned to her a base offense level of twenty-eight
under USSG § 2D1.1. See Apprendi v. New Jersey, 

(2000); United
States v. Diaz, 

, 684 (8th Cir. 2002) (“[T]he first step in sentencing is
for the district court to make findings [including that of drug quantity] and calculate
a sentencing range based on those findings.”). The district court’s determination was
based in part on evidence presented by the government’s expert, criminalist Patricia
Krahn, concerning “the size or capability of [the] laboratory involved.” USSG §
2D1.1., cmt. note 12; United States v. Hunt, 

, 1196 (8th Cir. 1999) (“To
determine the manufacturing capability of the laboratory, it is appropriate to rely upon
the testimony of a qualified expert.”); see also United States v. Eide, 

,
705 (8th Cir. 2002). Krahn analyzed samples seized on May 10, 2000, from
Hylback’s residence at 114 Maple Street in Kensett, Iowa. Krahn also analyzed

                                          -6-
samples from materials seized from Kessler’s residence at 106 Main Street, Joice,
Iowa, on May 10, 2000. Krahn’s analysis of the evidence seized at the labs indicated
that there was a high ratio of methamphetamine to the by-product CMP and the
precursors. This ratio indicates a forty to fifty per cent yield of methamphetamine.
After discounting the yield accordingly, Krahn testified that the labs would have
yielded approximately thirty-six to forty-five grams of pure methamphetamine.
Accordingly, the evidence amply supported the district court’s finding upon which
it calculated correctly the applicable base offense level. USSG § 2D1.1(a)(3).

      The judgment is affirmed.

      A true copy.

            Attest:

                CLERK, U.S. COURT OF APPEALS, EIGHTH CIRCUIT.




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