United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT
      ___________

      No. 08-2940
      ___________

                                      *
United States of America,             *
                                      *
            Appellee,                 *
                                      *
      v.                              *
                                      *
Ignacio Montes-Medina,                *
                                      *
            Appellant.                *


      ___________
                                              Appeal from the United States
      No. 08-2970                             District Court for the
      ___________                             District of Nebraska.

                                      *
United States of America,             *
                                      *
            Appellee,                 *
                                      *              [PUBLISHED]
      v.                              *
                                      *
Carlos A. Vega-Toscano, also          *
known as Jose,                        *
                                      *
            Appellant.                *
                                ________________

                             Submitted: April 17, 2009
                                 Filed: July 7, 2009
                                ________________

Before LOKEN, Chief Judge, HANSEN and COLLOTON, Circuit Judges.
                            ________________

HANSEN, Circuit Judge.

      Following an undercover narcotics investigation involving controlled purchases
of methamphetamine, a six-count indictment charged Ignacio Montes-Medina
(Montes-Medina) and Carlos A. Vega-Toscano (Vega-Toscano), together with two
others, with various drug trafficking crimes. Vega-Toscano entered a guilty plea to
one count of possession with intent to deliver methamphetamine, and a jury convicted
Montes-Medina on one count of conspiracy to distribute methamphetamine and one
count of possession with intent to distribute methamphetamine. The district court1
sentenced both Vega-Toscano and Montes-Medina to 188 months of imprisonment.
Vega-Toscano appeals his sentence, and Montes-Medina appeals the denial of his
suppression motion, his convictions, and his sentence. We affirm.

                                         I.

      The evidence at Montes-Medina's trial demonstrated that in the fall of 2006, law
enforcement agents used Sergio Zamarripa (Zamarripa) as a cooperating informant in
controlled purchases of methamphetamine in Grand Island, Nebraska. In October
2006, Zamarripa purchased methamphetamine in a controlled buy from Ramon
Schachta, who had initially purchased it by contacting Montes-Medina and taking


      1
      The Honorable Warren K. Urbom, United States District Judge for the District
of Nebraska.

                                         -2-
delivery from Vega-Toscano. Zamarripa testified that he first met Montes-Medina in
November 2006. By telephone, Zamarripa had arranged to meet Montes-Medina and
Vega-Toscano at Zamarripa's house. Montes-Medina and Vega-Toscano arrived in
a maroon truck, and Montes-Medina identified himself as the boss in their
methamphetamine trade. Zamarripa told the two men that he wanted to work with
them. Montes-Medina then gave Zamarripa a small amount of methamphetamine
from his pocket as a sample and indicated that the price per ounce was $1,000. They
exchanged telephone numbers, and Zamarripa later called and negotiated a deal with
Montes-Medina to purchase one ounce of methamphetamine for $800 at the Five
Points Car Wash in Grand Island. On December 12, 2006, Zamarripa, under law
enforcement surveillance, went to the Five Points Car Wash for the negotiated
transaction. Vega-Toscano arrived alone with the methamphetamine and fronted the
drugs, allowing Zamarripa to pay later. Law enforcement officers then followed
Vega-Toscano's vehicle, which parked at 229 Darr Street in Grand Island.

       The following week, Zamarripa telephoned Montes-Medina to negotiate another
transaction, and they agreed it would take place at the Capital Car Wash in Grand
Island on December 19, 2006. Law enforcement officers fitted Zamarripa with a wire.
He made a recorded call to Montes-Medina using the number Montes-Medina had
given him. Law enforcement officers also simultaneously conducted surveillance at
229 Darr Street. There, they observed two people enter a maroon truck and drive off.
Officers followed the truck, losing it once but relocating it at another residence, 415
East Hall, in Grand Island. The officers observed two adult males in the driveway
enter the truck and drive toward Capital Car Wash, and Zamarripa identified them as
Montes-Medina and Vega-Toscano. Vega-Toscano and Montes-Medina arrived at the
car wash in the maroon truck, and both entered Zamarripa's vehicle to negotiate and
carry out the deal. Montes-Medina instructed Vega-Toscano to retrieve the
methamphetamine from the maroon truck, which he did, and Montes-Medina also
gave Zamarripa a smaller quantity of methamphetamine of a different quality. A car
wash employee then instructed them to leave.

                                         -3-
        Zamarripa again recorded a telephone conversation with both Montes-Medina
and Vega-Toscano, arranging another controlled purchase. Zamarripa arranged to
purchase a kilo of methamphetamine on December 27, 2006, at the Kohl's department
store parking lot in Grand Island. Montes-Medina and Vega-Toscano were waiting
there without the kilo (2.2 pounds) when Zamarripa arrived, but they promised
Zamarripa they could get a half pound of methamphetamine in about 15 minutes, and
Montes-Medina set the price at $7,500. They agreed to meet for this deal at another
car wash on Locust Street, and Montes-Medina and Vega-Toscano left the parking lot
in a green Toyota Celica. Prearranged surveillance units at Kohl's were reassigned.
Investigator Pederson and Detective Witt drove to 415 East Hall Street where they
observed the green Toyota Celica in the driveway. They waited for the two men to
come out of the house and get into the vehicle, and they followed it to the car wash,
where the passenger, Vega-Toscano, alighted and walked toward the car wash. Seeing
something in his waistband, officers decided to arrest Vega-Toscano as he approached
the car wash. During the pat-down, a package of 222.68 grams of methamphetamine
fell from his pant leg; the weight being just shy of one-half pound.

       Investigators Rick Conrad and Scott Javins were in a second surveillance unit
sent to the car wash on December 27, 2006. They observed the passenger get out of
the green Toyota and saw the driver of the car park approximately a block away from
the car wash, exit the vehicle, and enter a residence. The owner of the residence
opened the door to the officers and pointed out Montes-Medina on the couch. The
officers found no drugs on his person, but he was in possession of the cell phone
bearing the number that Zamarripa had been calling to arrange the purchases. They
arrested Montes-Medina.

      Following the arrests, Investigator Mark Dreher applied for and obtained a
search warrant for the residence located at 415 East Hall, from which Montes-Medina
and Vega-Toscano twice had been seen leaving prior to methamphetamine deals with
Zamarripa. Investigator Dreher's affidavit indicated that a cooperating individual had

                                         -4-
purchased methamphetamine from two Hispanic males, that the affiant had prior
knowledge of the two Hispanic males, that they went to this residence in a green
Toyota Celica after making arrangements to sell the cooperating individual half a
pound of methamphetamine, and that Investigator Jim Pederson had observed them
exit the residence at 415 East Hall, leave in the green Toyota, and drive to the area of
the car wash where they were arrested. Pursuant to the warrant, officers seized several
small plastic bags containing a substance that proved to be methamphetamine in
various quantities and purity levels.

       Montes-Medina moved to suppress the evidence seized as a result of the search,
challenging the affidavit and the finding of probable cause on the grounds that
material omissions and a lack of specificity as to the cooperating individual's
reliability rendered the warrant lacking in probable cause. The district court denied
the motion to suppress. Vega-Toscano entered a guilty plea to Count 5, charging
possession with intent to deliver 50 grams or more of methamphetamine.2 See 18
U.S.C. § 2; 21 U.S.C. § 841(a)(1). Montes-Medina proceeded to trial, after which the
jury convicted him on Count 1 of conspiracy to distribute 50 to 500 grams of a
mixture or substance containing methamphetamine, see 18 U.S.C. § 2; 21 U.S.C.
§ 846; and on Count 5 of possession with intent to distribute 50 to 500 grams of a
mixture or substance containing methamphetamine and 50 grams or more of actual
methamphetamine, see 18 U.S.C. § 2; 21 U.S.C. § 841(a)(1).

      At Vega-Toscano's sentencing, the Government attributed to him a total
quantity of 155.18 grams of actual methamphetamine based on laboratory reports.
The Government and Vega-Toscano stipulated that the purity analyses of the various
quantities comprising that total are subject to a 10% margin of error. The Presentence
Investigation Report (PSR) recommended a base offense level of 34 based upon the

      2
        Vega-Toscano also pleaded guilty to the forfeiture allegations of Count 6, but
the Government moved to dismiss this count, and the district court granted the motion.
It is not at issue in this appeal.

                                          -5-
drug quantity, a two-level adjustment for obstruction of justice, and a criminal history
category I, resulting in an advisory Guidelines sentencing range of 188 to 235 months
of imprisonment. Vega-Toscano objected to the base offense level. The Sentencing
Guidelines provide that the break point between a base offense level of 32 and a level
34 is 150 grams of actual methamphetamine. See U.S. Sentencing Guidelines Manual
(USSG) §§ 2D1.1(c)(3) & (4) (2007). Vega-Toscano argued that he must be given the
benefit of the 10% margin of error in the quantity determination, which would result
in a quantity less than 150 grams and would yield the lower advisory Guidelines
range. The district court overruled the objection, finding that a base offense level 34
was appropriate. The district court sentenced Vega-Toscano at the low end of the
applicable Guidelines range to 188 months of imprisonment.

       Montes-Medina's sentencing calculation also began at base offense level 34.
The district court overruled his objection to a two-level enhancement for obstruction
of justice. The PSR recommended the enhancement because Montes-Medina had
called Vega-Toscano to testify knowing he would lie. The district court found that
Vega-Toscano had committed perjury on at least eight occasions at trial, testifying that
Montes-Medina was never involved in the distribution of methamphetamine and
asserting that Montes-Medina's voice is not on the recording of negotiations for the
delivery of methamphetamine on December 27, 2006. The district court also found
circumstances indicating that Montes-Medina knew Vega-Toscano would lie on his
behalf. With this enhancement, the resulting advisory sentencing range was 188 to
235 months of imprisonment, and the district court imposed a sentence of 188 months
of imprisonment.




                                          -6-
                                            II.
                                            A.

       Vega-Toscano challenges his sentence, arguing solely that he should have
received the benefit of the 10% margin of error in the drug quantity determination
stipulated to by the Government, which in turn would have yielded a lower advisory
Guidelines range of 151 to 188 months. He does not contest on appeal the
enhancement for obstruction of justice. We review criminal sentences for an abuse
of discretion, first ensuring that the district court committed no significant procedural
error, such as failing to calculate the Guidelines sentencing range properly, and
second, for substantive reasonableness. Gall v. United States, 

, 

, 597 (2007); United States v. Vega-Iturrino, 

, 432-33 (8th Cir. 2009).
In determining whether a sentencing court has committed procedural error, we review
the court's application of the Guidelines de novo and its findings of fact, such as the
findings regarding drug quantity, for clear error. United States v. Clarke, 

, 955 (8th Cir. 2009). We are permitted on appeal to apply a presumption of
reasonableness to a properly calculated within-Guidelines sentence. Rita v. United
States, 

, 347 (2007).

        The district court did not commit procedural error in its calculation of the drug
quantity attributable to Vega-Toscano. At sentencing, the Government bears the
burden of proving drug quantity by a preponderance of the evidence. United States
v. Atkins, 

, 1211 (8th Cir. 2001). The Government presented evidence
supported by laboratory reports that a quantity of 155.18 grams of methamphetamine
was attributable to Vega-Toscano, and both parties stipulated to the 10% margin of
error. The district court, as the fact finder, was free to rely upon the laboratory results,
and that finding is supported by a preponderance of the evidence. There was no
evidentiary basis for applying the margin of error in one direction or the other. As
with any evidence offered by either party at sentencing, the court, as the finder of fact,
is free to accept or to reject the evidence in whole or in part. We have held that even

                                            -7-
"[w]hen no quantity has been recovered, the government may prove the purity of
quantities attributed to the defendant by circumstantial evidence, for example, a
conspirator's reliable testimony . . . or an expert's testimony as to the normal purity of
methamphetamine produced in a lab." United States v. Houston, 

, 879
(8th Cir. 2003). The record here includes laboratory test results of the
methamphetamine actually recovered, and Vega-Toscano's only argument is that he
should receive the benefit of the margin of error to lower the total amount. While the
district court was free to apply the stipulated 10% margin of error in either direction,
this is not a case where a district court applied a margin of error in a manner that
raised the drug quantity to a higher offense level. We hold only that the district court
was not required to use the lab's margin of error to drive the drug quantity down into
a lower offense level and that the district court's quantity determination in this case is
well supported by the record. "In reviewing the drug quantity finding for clear error,
we must affirm unless the entire record firmly convinces us that a mistake has been
made." 

. Nothing in this record convinces us that a mistake
has been made. Finding no significant procedural error in the district court's
calculation of the advisory Guidelines range, we apply the presumption of
reasonableness, which has not been rebutted, and affirm this bottom-of-the-range
sentence as to Vega-Toscano.

                                            B.
                                             1.
       Montes-Medina first challenges the district court's denial of his suppression
motion on grounds that the warrant application did not establish probable cause. We
review the district court's findings of fact for clear error and its conclusions of law de
novo. United States v. Hart, 

, 913-14 (8th Cir. 2008), cert. denied, 

(2009). The Fourth Amendment requires probable cause to be shown for
the issuance of a warrant. 

"Where there is no evidentiary hearing before
the magistrate judge, the probable cause determination must be based upon only the
information which is found within the four corners of the affidavit." United States v.

                                           -8-
Hudspeth, 

, 674 (8th Cir. 2008) (internal marks omitted). We must
consider the totality of the circumstances to determine whether an affidavit is
sufficient to demonstrate probable cause. 

. Probable cause
exists if the warrant application and affidavit describe circumstances showing "a fair
probability that contraband or evidence of a crime will be found in a particular place,"
and our duty on appeal "is simply to ensure that the magistrate had a substantial basis
for concluding that probable cause existed." Illinois v. Gates, 

, 238-39
(1983) (internal marks omitted).

       A defendant may be entitled to an evidentiary hearing in the district court to
attack the veracity of the warrant affidavit if "the defendant makes a substantial
preliminary showing" that a false statement knowingly, intentionally, or recklessly
was included in the warrant affidavit and was "necessary to the finding of probable
cause." Franks v. Delaware, 

, 155-56 (1978). The defendant must make
this showing by supporting the allegations with an offer of proof. See United States
v. DeBuse, 

, 1075 (8th Cir. 2002). When information is alleged to have
been omitted from an affidavit, the warrant may be invalid if the defendant can prove
by a preponderance of the evidence that the applying officer omitted facts in reckless
disregard of whether the omission made the affidavit misleading and that, if
supplemented by the "clearly critical" information omitted, the affidavit would not
have supported a finding of probable cause. United States v. Williams, 

,
557 & 559 (8th Cir. 2007) (internal marks omitted).

       The district court detailed several important assertions from the affidavit and
concluded that, when read in a commonsense manner, they are sufficient to support
a finding of probable cause. We agree. The affidavit recounts the basic facts that a
cooperating individual communicated with two Hispanic males who had previously
contacted him to arrange a methamphetamine purchase. The Hispanic males agreed
to sell various amounts of methamphetamine to the cooperating individual and the
affiant stated he had prior knowledge that the suspects had gone to the 415 East Hall

                                          -9-
residence to retrieve methamphetamine in the past. On this current occasion,
Investigator Jim Pederson saw them exit the residence, enter the green Toyota, and
drive to the prearranged place for the controlled purchase. One of the Hispanic males
was arrested there with approximately one-half pound of methamphetamine, and the
affidavit states that the two Hispanic males had told the cooperating individual that
"all the rest of the Methamphetamine was at the house that they had to go get it from."
(Montes-Medina's Add. at 8, Dreher Affidavit at 2.)

        The district court correctly viewed the affidavit in "'a practical, commonsense'"
manner, considering the totality of the circumstances. See United States v. Carter, 

, 714 (8th Cir. 2005) (quoting 

). When read as a
whole, it is sufficiently clear that the affidavit's references to a residence and a house
are references to the 415 East Hall address that is the subject of the warrant. The
cooperating individual's reliability can be found adequate from the detail of the
information and the controlled buys referenced. "[E]ven if we entertain some doubt
as to an informant's motives, his explicit and detailed description of alleged
wrongdoing, along with a statement that the event was observed first hand, entitles his
tip to greater weight than might otherwise be the case." 

. The
officer in this case reliably corroborated the cooperating individual's account by
monitoring the negotiation of two controlled purchases, observing the suspects at the
residence before the controlled buys, and setting forth actions by the cooperating
individual implicating himself in criminal activity, all of which lends support to the
finding of probable cause in the warrant application. See United States v. Pennington,

, 742-43 (8th Cir.), cert. denied, 

(2002).

       Additionally, Montes-Medina did not demonstrate that the affidavit included
any deliberate or reckless falsehoods. His assertion that the affidavit omitted
information that the officers had entered the residence prior to seeking a warrant does
not present information that was clearly critical to or that affected the probable cause



                                          -10-
determination. Accordingly, the district court did not abuse its discretion in denying
a Franks hearing. See United States v. Crissler, 

, 833-34 (8th Cir. 2008).

                                          2.
       Montes-Medina challenges the sufficiency of the evidence to sustain his
convictions for conspiracy and the possession of methamphetamine with intent to
distribute, asserting that there was no evidence that he ever actually possessed any
methamphetamine. We review a challenge to the sufficiency of the evidence de novo,
viewing the evidence and all reasonable inferences in the light most favorable to the
verdict. United States v. Farrell, 

, 366 (8th Cir. 2009). We will reverse
only if no reasonable jury could have found him guilty beyond a reasonable doubt.

the lengthy trial transcript, summarized above, we have no
trouble concluding that the evidence in this case is sufficient to sustain both of
Montes-Medina's convictions. "A conspiracy conviction requires proof that the
defendant entered into an agreement with at least one other person to sell
methamphetamine," and "[a] conviction for possession with intent to distribute
requires knowing possession of the methamphetamine." United States v. Salvador,

, 992 (8th Cir. 2005) (internal marks omitted). "Proof of constructive
possession is sufficient to satisfy the element of knowing possession." 

omitted). There was ample evidence from which a jury could conclude that
Montes-Medina acted jointly with Vega-Toscano in conspiring to sell
methamphetamine to Zamarripa. That evidence includes Zamarripa's testimony, law
enforcement officers' testimony, recorded telephone conversations with Montes-
Medina's voice negotiating the deals, and controlled purchases with Montes-Medina
present or nearby. Indeed, the evidence strongly indicated that Montes-Medina was
in charge of the drug deals. While Montes-Medina was not arrested in actual
possession of methamphetamine, the evidence supports a finding beyond a reasonable
doubt that he was in constructive possession of the methamphetamine that Vega-

                                        -11-
Toscano delivered. He negotiated the transactions with Zamarripa, set the prices for
the methamphetamine, and was seen going into and coming out of the residence at 415
East Hall prior to the controlled buys. Further, he was in the vehicle with the
methamphetamine on more than one occasion, and he was present during at least one
of the transactions. See 

(finding constructive possession where
defendant was present at a transaction, he was in the car that contained the drugs, and
testimony indicated he knew the location of the drugs). "Knowledge of the presence
of contraband, plus the ability to control that contraband either directly or through
another person establishes constructive possession." 

We conclude that the
evidence is sufficient to sustain Montes-Medina's convictions on both drug charges.

                                           3.
       Finally, Montes-Medina argues that the district court erred in enhancing his
base offense level at sentencing on the ground that he engaged in the obstruction of
justice. See USSG § 3C1.1. "We give great deference to a district court's decision to
impose an obstruction of justice enhancement" and will not reverse unless the findings
are insufficient. United States v. Hance, 

, 911 (8th Cir. 2007) (internal
marks omitted). The district court must find the predicate facts supporting an
enhancement for obstruction of justice by a preponderance of the evidence, and we
review those findings for clear error. United States v. Aleman, 

, 1163
(8th Cir. 2008), cert. denied, 

(U.S. Jun. 1, 2009) (No. 08-10151).
Suborning perjury and providing materially false information to a judge is conduct
that amounts to an obstruction of justice. See USSG § 3C1.1, comment. (n.4); see
also United States v. Negrete, 

, 921 (8th Cir. 2008) (holding the
obstruction enhancement is appropriate "if the defendant has committed perjury or
suborned perjury by another witness" (internal marks omitted)). The district court
pointed to eight very specific portions of Vega-Toscano's testimony to support the
finding that Vega-Toscano committed perjury at the trial. (See Montes-Medina's Sent.
Tr. at 28-30.) In those portions of the transcript, Vega-Toscano testified repeatedly
that he was alone during recorded telephone conversations that obviously involve

                                         -12-
three distinct voices, one of which was identified as the voice of Montes-Medina. He
also testified that he was alone with Zamarripa in a vehicle during a controlled buy
when Zamarripa and law enforcement officers all observed Montes-Medina's
presence. The district court's ultimate finding that Vega-Toscano intentionally lied
to the jury is supported by these specific references to his testimony. See United
States v. Whiting, 

, 850 (8th Cir. 2008) (concluding that the district court
adequately supported the obstruction enhancement by pointing to specific parts of the
testimony it found to be intentional lies). The district court also found that Montes-
Medina knew Vega-Toscano would lie on the stand, pointing again to specific
statements in the record and reasonable inferences from that evidence. The record
shows that Montes-Medina's counsel established that counsel had never spoken to the
witness, yet Montes-Medina's counsel represented to the court that he knew Vega-
Toscano would testify that Montes-Medina was not involved. The district court drew
the reasonable and permissible inference that Montes-Medina and Vega-Toscano,
housed at the same jail, had spoken at the jail about the content of Vega-Toscano's
proposed testimony and that Montes-Medina had told his lawyer what that testimony
would be. We conclude that the district court did not clearly err in applying the
obstruction of justice enhancement. Finding no significant procedural errors in the
district court's calculation of the advisory Guidelines range, we apply the unrebutted
presumption of reasonableness and affirm Montes-Medina's sentence.

                                          III.

      Accordingly, we affirm the judgment of the district court in both cases.
                   ______________________________




                                         -13-