United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT
                                   ___________

                                   No. 07-2374
                                   ___________

United States of America,               *
                                        *
             Appellee,                  *
                                        * Appeal from the United States
      v.                                * District Court for the
                                        * Northern District of Iowa.
Alberto Villalpando,                    *
                                        * [UNPUBLISHED]
             Appellant.                 *
                                   ___________

                             Submitted: December 3, 2008
                                Filed: January 9, 2009
                                 ___________

Before MURPHY, BYE, and BENTON, Circuit Judges.
                           ___________

PER CURIAM.

       Alberto Villalpando appeals the judgment of the district court1 entered upon a
jury verdict finding him guilty of conspiring to distribute methamphetamine and
cocaine, in violation of 21 U.S.C. §§ 841(a)(1), (b)(1)(A), (b)(1)(C) and 846; and of
distributing methamphetamine, in violation of 21 U.S.C. § 841(a)(1), (b)(1)(A). He
challenges the sufficiency of the evidence and the application of an obstruction-of-
justice sentencing enhancement. For the reasons that follow, we affirm.



      1
        The Honorable Mark W. Bennett, United States District Judge for the Northern
District of Iowa.
       The trial testimony of drug task force officers and forensic chemists established
the following. A confidential informant (CI) arranged to make a controlled purchase
of a pound of methamphetamine from Margarito and Fernando Cortez at the CI’s
residence on November 22, 2005. That day, the CI wore a hidden video camera and
an audio device that recorded her conversations and transmitted them to officers
monitoring the events. Margarito was standing outside the CI’s residence when a car
occupied by Villalpando and another person arrived. Margarito then went inside,
where his delivery of a package to the CI was captured on the video camera and audio
recording device. The CI gave the package to the officers, and forensic chemists
determined it contained 434.2 grams of methamphetamine mixture, which at 19%
purity amounted to 82.4 grams of actual methamphetamine.

       In April 2006, officers executed a search warrant at the residence of Fernando
and Margarito Cortez, recovering a quantity of cocaine and a substance commonly
used to “cut,” or dilute, cocaine. Upon Margarito’s arrest, he identified Villalpando
as his cocaine supplier and contacted Villalpando to arrange a purchase. Officers
observing Villalpando’s residence saw him leave, followed him to Margarito’s
residence, arrested Villalpando, and found five bags of cocaine in his pocket.
Additional bags of cocaine were found at Villalpando’s residence after he told officers
where to look.

       During Villalpando’s post-arrest interview, which was recorded and played for
the jury, he stated that for about two months he had obtained cocaine from someone
named Chango, and that he would deliver cocaine to Margarito Cortez, who would
then cut it to double his quantity. Villalpando also acknowledged selling a pound of
methamphetamine several months earlier, and he described the details of the
transaction. At trial, Villalpando testified that he had been involved with cocaine, that
he had delivered it to Margarito in the past, that he had cocaine on his person when
he was arrested, and that cocaine was found at his residence. He testified that he had
never delivered methamphetamine, however, and that his contrary statements to the

                                           -2-
police were false. The jury found him guilty of conspiring to distribute 50 grams or
more (but less than 500 grams) of methamphetamine mixture, 50 grams or more of
actual methamphetamine, and an unspecified quantity of powder cocaine; and guilty
of distributing 50 grams or more of actual methamphetamine.

       The calculations for an advisory Guidelines imprisonment range of 151-188
months included a 2-level increase to the base offense level for obstruction of justice,
based on Villalpando’s having committed perjury at trial. At sentencing, the district
court overruled his objection to the enhancement, finding by a preponderance of the
evidence that Villalpando was untruthful at trial when he denied delivering
methamphetamine. The district court sentenced him to concurrent terms of 151
months in prison, and 5 years of supervised release.

        First, we conclude that Villalpando’s post-arrest admissions and his consistent
trial testimony regarding his delivery of cocaine sufficiently established that two or
more persons reached an agreement to distribute cocaine, that Villalpando voluntarily
and intentionally joined the agreement, and that he knew its essential purpose. See
United States v. Harris, 

, 931 (8th Cir. 2007) (elements of conspiracy to
distribute controlled substance); United States v. Titlbach, 

, 696-97 (8th
Cir. 2003) (slight evidence connecting defendant to conspiracy may be enough to
sustain conviction; government need only prove defendant tacitly agreed to participate
and intended conspiracy’s unlawful goal); United States v. Shepherd, 

,
969 (8th Cir. 2002) (evidence is viewed in light most favorable to verdict, and is
sufficient if any rational trier of fact could have found essential elements of crime
beyond reasonable doubt).

       We further conclude that the testimony of one of the forensic chemists, along
with the testimony of the officers conducting surveillance and Villalpando’s post-
arrest admission--the retraction of which the jury apparently disbelieved--that he had
delivered a pound of methamphetamine, constituted ample evidence supporting the

                                          -3-
jury’s special verdict that Villalpando was responsible for less than 500 but at least
50 grams of methamphetamine mixture and more than 50 grams of actual
methamphetamine, notwithstanding slight uncertainties based on sample testing. See
Gibson v. Bowersox, 

, 374 (8th Cir. 1996) (proof of existence of
controlled substance need not be by direct evidence; use of random testing is
permissible to establish substance contained cocaine base for sentencing purposes;
every particle of substance need not be tested); United States v. Stroh, 

,
440 (8th Cir. 1999) (in reviewing sufficiency of evidence, reviewing court can neither
weigh evidence nor assess credibility of witnesses); cf. 

(chemist’s trial testimony about theoretical yields of methamphetamine based on
precursor elements was sufficient to support jury’s special verdict on quantity).

       Finally, we hold that the district court did not commit clear error in finding that
Villalpando perjured himself at trial when he denied any involvement with
methamphetamine, given the surveillance evidence and his post-arrest admissions, and
we conclude that the obstruction-of-justice enhancement was permissible. See United
States v. Molina, 

, 1058 (8th Cir. 1999) (findings of fact in support of
obstruction-of-justice enhancement reviewed for clear error, and application of
Guidelines reviewed de novo; perjury at trial constitutes obstruction of justice).

      Accordingly, we affirm.
                     ______________________________




                                           -4-