United States Court of Appeals
                             FOR THE EIGHTH CIRCUIT
                                 ________________

                                    No. 09-1454
                                 ________________

United States of America,                *
                                         *
             Appellee,                   *
                                         * Appeal from the United States
      v.                                 * District Court for the
                                         * Western District of Missouri.
Chris Coleman,                           *
                                         *
             Appellant.                  *
                                    ___________

                              Submitted: September 22, 2009
                                 Filed: October 30, 2009
                                  ___________

Before MELLOY, BEAM and GRUENDER, Circuit Judges.
                          ___________

GRUENDER, Circuit Judge.

       Chris Coleman was convicted after a jury trial of one count of conspiracy to
distribute and possess with intent to distribute fifty grams or more of crack cocaine
between December 1, 2006, and June 8, 2007, in violation of 21 U.S.C. §§ 841(a)(1),
(b)(1)(A), 846, and 851 (“Count 1”), and one count of aiding and abetting the
possession with intent to distribute five grams or more of crack cocaine on May 9,
2007, in violation of 21 U.S.C. §§ 841(a)(1), (b)(1)(B), and 18 U.S.C. § 2 (“Count 7”).
The district court1 denied Coleman’s motion for judgment of acquittal and sentenced
him to life in prison on Count 1 and a concurrent term of 480 months in prison on
Count 7. Coleman appeals, arguing that the Government presented insufficient
evidence to support a conviction on either count. He also argues that the district court
abused its discretion by excluding the testimony of a proposed expert witness about
the benefits that Coleman’s co-conspirators could receive from cooperating with the
Government. For the following reasons, we affirm.

I.    BACKGROUND

      On September 12, 2007, a federal grand jury returned a seven-count indictment
charging Coleman and four other defendants with various drug offenses. David
Hathaway, Cornelius Robinson, and Courtney Baker each pled guilty to one count of
conspiracy to distribute crack and received sentences of 60, 104, and 120 months in
prison, respectively. Gwendolyn Bates pled guilty to one count of distribution of
crack and received a sentence of 60 months in prison. Coleman pled not guilty to
Counts 1 and 7 and proceeded to trial.

       In his plea agreement with the Government, Robinson agreed to testify against
Coleman. Elmo Brown, who pled guilty to conspiracy to distribute crack in a separate
case, also agreed to testify against Coleman. In an attempt to undermine the
credibility of these witnesses, Coleman intended to call a former Assistant United
States Attorney to testify as an expert about the sentencing reductions that Robinson
and Brown could receive as a result of their cooperation with the Government. The
district court found that this testimony would not assist the jury and granted the
Government’s motion in limine to exclude it.




      1
       The Honorable Fernando J. Gaitan, Jr., Chief Judge, United States District
Court for the Western District of Missouri.

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       At trial, Robinson testified that in 2006 and 2007 he lived with Bates at her
house in Grandview, Missouri. While he lived with Bates, Robinson regularly
obtained crack from Coleman for distribution. When Robinson owed Coleman
money, he would allow Coleman to cook crack at Bates’s house. Coleman “ran” the
house when he cooked there and required customers to come inside to buy crack. As
many as fifty customers per day bought crack at Bates’s house. Robinson testified
that he saw Coleman cook crack at least eighteen times and that Coleman cooked “no
more than two, three, four ounces at a time.” When Coleman suspected that the police
were watching Bates’s house, he moved the operation to a nearby duplex, where he
continued to cook and distribute crack. Bates also sold crack for Coleman, and
Coleman regularly discussed with Bates the amount of money she owed him in
Robinson’s presence.

       Brown testified that he saw Coleman sell crack to Robinson and Bates for resale
several times and that Coleman and Robinson frequently argued about “the money not
being right.” He also testified that as many as fifty customers came to Bates’s house
each weekend to buy crack. Finally, Brown testified that he saw Coleman cook crack
on at least two occasions.

       The Government also presented the testimony of two undercover police
officers, Detectives Justin Rigot and Mark Corbin. Detective Rigot testified that he
bought       grams of crack from Baker on December 29, 2006. A few days later, on
January 2, 2007, Detective Rigot met Baker again and asked to purchase an ounce of
crack. Rigot and Baker negotiated the sale while Rigot was sitting in a parked car in
front of a residential home near the duplex. Coleman was standing in front of the
home in the driveway approximately twenty feet away. Baker went back and forth
between Coleman and Rigot several times attempting to finalize the sale. At trial, the
Government played for the jury a recording Detective Rigot made of his conversation
with Baker. The recording did not capture Baker’s discussions with Coleman, but
throughout his conversation with Detective Rigot, Baker claimed to be relaying

                                         -3-
Coleman’s concerns. Baker eventually told Rigot that Coleman refused to approve
the sale because he suspected that Rigot was a police officer. Later that evening,
however, Baker sold Rigot 5.87 grams of crack at a separate location.

       Detective Corbin testified that he purchased 2.64 grams of crack from Bates on
May 2, 2007. Corbin met Bates at her house and drove her to the duplex. He parked
the car, gave Bates $200 in cash, and waited in the car while Bates went inside. Bates
returned a short time later and handed Corbin a plastic bag containing several rocks
of crack.

      Detective Corbin also testified that he purchased 27.49 grams of crack from
Robinson on May 9, 2007, in front of Bates’s house. Corbin waited outside while
Robinson retrieved the crack from the house. Robinson corroborated this testimony
and added that Coleman personally supervised the May 9, 2007 sale. According to
Robinson, Detective Corbin gave him $1800 in cash, which he took inside and handed
to Coleman. Coleman did not have enough crack on hand to fill Corbin’s order, so he
sent Baker to buy the appropriate amount of crack from a different dealer. When
Baker returned, Coleman took the crack and handed it to Robinson. Robinson then
delivered the crack to Corbin.

      At the close of the Government’s case, Coleman moved for a judgment of
acquittal, which the district court denied. The jury found Coleman guilty on Counts
1 and 7.

II.   DISCUSSION

      Coleman argues that the district court erred by denying his motion for judgment
of acquittal because the evidence was insufficient to support a conviction on either
Count 1 or Count 7. We review de novo challenges to the sufficiency of the evidence
presented at trial. United States v. Ironi, 

, 689-90 (8th Cir. 2008). In

                                         -4-
conducting this review, we consider the evidence in the light most favorable to the
jury’s verdict and draw all reasonable inferences in the Government’s favor. United
States v. McAtee, 

, 1104 (8th Cir. 2007). We do not weigh the evidence
or assess the credibility of witnesses, and we will reverse a conviction only if no
reasonable jury could have found the defendant guilty beyond a reasonable doubt.
United States v. Santana, 

, 853 (8th Cir. 2008).

      To convict Coleman on Count 1, the Government was required to prove beyond
a reasonable doubt that “two or more persons reached an agreement to distribute or
possess with intent to distribute a controlled substance, that the defendant voluntarily
and intentionally joined the agreement, and that at the time he joined the agreement,
he knew its essential purpose.” United States v. Harris, 

, 931 (8th Cir.
2007), cert. denied, 552 U.S. ---, 

(2008). The Government is not
required to present direct evidence of an explicit agreement, and the jury may rely on
circumstantial evidence to infer a “tacit understanding” among co-conspirators.
United States v. Jiminez, 

, 1146 (8th Cir. 2007) (quoting United States
v. Cabrera, 

, 1245 (8th Cir. 1997)).

       In this case, the evidence showed that Coleman repeatedly provided crack to
Robinson, Baker, Bates, and others for resale. This conduct alone provided a
sufficient basis for the jury to infer that Coleman knowingly and intentionally joined
an agreement to distribute crack. See United States v. Ramirez, 

, 784
(8th Cir. 2003). Furthermore, Coleman was an active participant in the drug
operation. Coleman cooked the crack and “ran” the house out of which it was sold.
He supervised individual transactions and kept track of the money that his distributors
owed him. Based on this evidence, a reasonable jury could find beyond a reasonable
doubt that Coleman participated in a conspiracy to distribute crack cocaine.

      Coleman also argues that the Government failed to prove that the conspiracy
involved fifty grams or more of crack. We disagree. The Government presented

                                          -5-
evidence that Detectives Rigot and Corbin obtained 42.79 grams of crack cocaine
through controlled buys from Robinson, Baker, and Bates, all of whom were involved
in the conspiracy with Coleman. A defendant is responsible for the drugs distributed
by his co-conspirators if their sales were made “(1) in furtherance of the conspiracy
and (2) were either known to [the defendant] or were reasonably foreseeable.” United
States v. Foxx, 

, 953 (8th Cir. 2008), cert. denied sub nom. Osborne v.
United States, 558 U.S. ---, No. 08-10424 (Oct. 5, 2009). Coleman regularly provided
crack to Robinson, Baker, and Bates for resale. He supervised their distribution
efforts and kept careful track of the money they owed him. A reasonable jury could
infer from this evidence that the sales to Detectives Rigot and Corbin by Coleman’s
co-conspirators were made in furtherance of the conspiracy and were reasonably
foreseeable to Coleman.

        After establishing that the controlled buys were attributable to the conspiracy,
the Government needed to present evidence that the conspiracy involved an additional
7.21 grams of crack cocaine to bring the total amount of crack involved in the
conspiracy to at least fifty grams. The distribution efforts of Coleman and his co-
conspirators attracted as many as fifty customers per day. Moreover, Robinson
testified that he saw Coleman cook crack at least eighteen times and that Coleman
cooked “no more than two, three, four ounces at a time.”2 A reasonable jury could
easily infer from this evidence that the conspiracy involved at least 7.21 grams of
crack cocaine in addition to the 42.79 grams that were sold to the undercover officers.
Considered in the light most favorable to the verdict, a reasonable jury could find
beyond a reasonable doubt that the conspiracy involved at least fifty grams of crack
cocaine. Therefore, we conclude that the evidence was sufficient to support
Coleman’s conviction on Count 1.




      2
       One ounce is equivalent to approximately 28.35 grams.

                                          -6-
        Coleman also argues that the evidence was insufficient to support his conviction
on Count 7. Again, we disagree. To prove the crime of aiding and abetting the
possession of drugs with intent to distribute, the Government must prove beyond a
reasonable doubt “(1) that the defendant associated himself with the unlawful venture;
(2) that he participated in it as something he wished to bring about; and (3) that he
sought by his actions to make it succeed.” United States v. Rojas, 

, 878
(8th Cir. 2004) (quoting United States v. McCracken, 

, 540 (8th Cir.
1997)). Robinson testified that Coleman personally supervised the sale of 27.49
grams of crack to Detective Corbin on May 9, 2007. Coleman took Detective
Corbin’s money from Robinson and sent Baker to obtain the amount of crack needed
to fill Corbin’s order. When Baker returned, Coleman handed the crack to Robinson,
knowing that Robinson would distribute it by delivering it to Detective Corbin.
Accordingly, the evidence of Coleman’s participation in the May 9, 2007 sale was
sufficient to support Coleman’s conviction on Count 7.

      Finally, Coleman argues that the district court abused its discretion by
excluding the testimony of a proposed expert “about the potential benefits that
Cornelius Robinson and Elmo Brown could receive as [a] result of their cooperation
with the government.” Appellant’s Br. at 32. We review a district court’s decision
about the admissibility of expert testimony for abuse of discretion. United States v.
Anderson, 

, 874 (8th Cir. 2006).

       In United States v. Davis, 

(8th Cir. 2006), we held that the district
court did not abuse its discretion by refusing to allow a Federal Public Defender to
testify as an expert about the “mechanics of the federal sentencing process” in order
to undermine the credibility of the government’s cooperating witnesses, 

also noted in Davis that defense counsel’s cross-examination, coupled with the
district court’s instructions, “sufficiently communicated to the jury the information it
needed to assess the incentives government witnesses had to stretch or shade the truth



                                          -7-
in order to obtain sentence reductions.” 

v. French, 

, 117 (8th Cir. 1993)).

        This case is very similar to Davis. Here, Coleman’s attorney cross-examined
both Robinson and Brown at length about their motivations for testifying against
Coleman and the benefits that they expected to receive as a result of their cooperation
with the Government. In addition, the district court instructed the jury that Robinson
and Brown might receive sentencing reductions as a result of their cooperation and
that it was the jury’s responsibility to weigh the credibility of these witnesses. Armed
with this information, the jury was equipped to evaluate the motivations of the
Government’s cooperating witnesses without the aid of additional testimony. In
reaching this conclusion, we decline to address whether such testimony could ever
assist a jury. We hold simply that the district court did not abuse its discretion by
excluding the testimony of Coleman’s proposed expert witness.3

III.   CONCLUSION

       For the foregoing reasons, we affirm the judgment of the district court.
                     ______________________________


       3
        Coleman also argues that the district court violated his rights under the Due
Process Clause of the Fifth Amendment and the Compulsory Process Clause of the
Sixth Amendment because the district court did not allow him to show the bias of the
Government’s cooperating witnesses. This argument lacks merit. The proposed
expert testimony was not the only method for Coleman to attack the credibility of the
cooperating witnesses. As noted above, Coleman’s attorney cross-examined both
Robinson and Brown extensively about their motivations for testifying. Such
vigorous cross-examination “is the principal means by which the believability of a
witness and the truth of his testimony are tested.” Davis v. Alaska, 

, 316
(1974). The district court’s decision to exclude the testimony of Coleman’s proposed
expert did not preclude Coleman from demonstrating the potential bias of the
Government’s cooperating witnesses.

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