United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT

           ___________

      Nos. 05-4301/06-1049
         ___________

United States of America,             *
                                      *
      Appellee/Cross-Appellant,       *
                                      *
      v.                              *
                                      *
Tyrone Judon, also known as           *
Antwon,                               *
                                      *
      Appellant/Cross-Appellee.       *

           ___________
                                             Appeals from the United States
      Nos. 05-4302/06-1050                   District Court for the
         ___________                         Northern District of Iowa.

United States of America,             *
                                      *
      Appellee/Cross-Appellant,       *
                                      *
      v.                              *
                                      *
Gladger Ross, Jr., also known as      *
Big,                                  *
                                      *
      Appellant/Cross-Appellee.       *

                               ________________

                       Submitted: September 28, 2006
                           Filed: January 5, 2007
                              ________________
Before LOKEN, Chief Judge, SMITH and GRUENDER, Circuit Judges.
                            ________________

GRUENDER, Circuit Judge.


      A jury convicted Gladger Ross, Jr. and Tyrone Judon each on several criminal
counts including conspiring to distribute crack and powder cocaine in violation of 21
U.S.C. §§ 841(a)(1) and 846. The district court sentenced Ross to 210 months in
prison and Judon to 50 months in prison. Ross and Judon appeal their convictions and
sentences. The Government cross-appeals both sentences. For the reasons that
follow, we affirm the convictions as to both defendants but vacate their sentences and
remand for resentencing.


I.    BACKGROUND


       In late 2004, officers of the North Central Iowa Narcotics Task Force used two
confidential informants, Brian Davis, Sr. and his son Brian Davis, Jr., to negotiate
several purchases of crack and powder cocaine from Ross and Judon in the Mason
City, Iowa area. Beginning in August and continuing through early November of that
year, the Davises bought several grams of cocaine, in both crack and powder forms,
from Ross and Judon. The Davises bought the cocaine primarily from Ross and
occasionally from Judon at Ross’s direction, often when Ross could not supply the full
quantity requested. Davis Jr. typically bought ten to twelve “rocks” of crack cocaine
at a time from Ross and Judon for $200. Davis Sr. typically bought in larger
quantities, paying $300 to $400 for an eighth of an ounce (about 3.5 grams) of either
powder or crack cocaine.


       On January 19, 2005, a federal grand jury indicted Ross and Judon along with
a third co-defendant, Holli Price, on multiple drug distribution charges, including one

                                         -2-
count for conspiring to distribute both crack and powder cocaine. Within weeks, Ross
was arrested on unrelated state charges. While in custody, Ross made inculpatory
statements to law enforcement with respect to the federal drug charges. Ross later
sought to suppress the statements, arguing that they were involuntary, but the district
court denied his suppression motion.


       At trial, the Government called both Davis Sr. and Davis Jr. as witnesses. In
addition to being a known drug user, Davis Jr. had been convicted in 2004 for assault
with intent to commit sexual abuse, for which he was sentenced to two years in prison.
Prior to trial, the Government moved in limine to exclude evidence of the sexual
nature of Davis Jr.’s conviction. The district court granted the Government’s motion
over resistance by Judon.


       At the close of the Government’s case-in-chief, Ross and Judon each orally
moved for judgment of acquittal, asserting that the Government’s evidence was
insufficient to prove the conspiracy charge. They also challenged the sufficiency of
the Government’s evidence that the conspiracy involved 50 grams or more of crack
cocaine, as charged in the indictment. The district court found that the evidence
presented was insufficient for a jury to conclude beyond a reasonable doubt that the
conspiracy involved 50 grams or more of crack cocaine. The district court otherwise
denied their motions. Ross and Judon renewed their motions for judgments of
acquittal at the close of all evidence. The district court denied these motions and
instructed the jury consistent with its ruling that the evidence presented was sufficient
only for the jury to find beyond a reasonable doubt that the conspiracy involved less
than 50 grams of crack cocaine.


      The jury convicted Ross for conspiring to distribute both crack and powder
cocaine, specifically finding Ross responsible for five or more but less than 50 grams
of crack cocaine. The jury also convicted Ross on six distribution counts, four
involving crack cocaine and two involving powder cocaine. The jury convicted Judon

                                          -3-
for conspiring to distribute both crack and powder cocaine, finding Judon responsible
for less than five grams of crack cocaine. The jury also convicted Judon on two crack
cocaine distribution charges and acquitted him on one charge of distributing powder
cocaine.


       After trial, Ross and Judon filed written motions for judgments of acquittal,
alternatively moving for new trials. Ross filed his motion pro se in conjunction with
a request for a new attorney. He chiefly argued that the Davises lacked credibility.
Judon also argued that the Davises were not credible, and he asserted that the district
court erred by limiting cross-examination into the circumstances surrounding Davis
Jr.’s prior conviction. In separate written orders, the district court denied both
motions.


       At sentencing, the district court found by a preponderance of the evidence that
Ross was responsible for 396.48 grams of crack cocaine and 396.48 grams of powder
cocaine, suggesting a guidelines base offense level of 34. Relying upon United States
v. Perry, 

(D.R.I. 2005), the district court eschewed the 100:1
drug equivalency ratio between crack cocaine and powder cocaine under the
guidelines and instead applied a 20:1 ratio. Describing its action as a Booker variance
under 18 U.S.C. § 3553(a), the district court recalculated Ross’s base offense level as
32 using the 20:1 ratio. Coupled with Ross’s criminal history category of VI, the
district court used the advisory guidelines sentencing range of 210 to 262 months and
sentenced Ross to 210 months’ imprisonment.


      The district court found by a preponderance of the evidence that Judon was
responsible for 19.53 grams of crack cocaine, placing him at a base offense level of
26. The district court likewise varied downward by rejecting the 100:1 crack to
powder cocaine ratio from the guidelines, instead employing a 20:1 ratio to recalculate
a new base offense level of 22. Judon also sought a two-level reduction for a
mitigating role in the offense under § 3B1.2 of the guidelines, which the district court

                                          -4-
denied. At level 22, Judon’s criminal history category of I yielded an advisory
guidelines sentencing range of 41 to 51 months, and the district court sentenced him
to 50 months’ imprisonment.


       Ross appeals the district court’s orders denying his motion to suppress and
denying his motion for a new trial. Ross also challenges the district court’s drug
quantity findings. Judon appeals the district court’s order denying his alternative
motions for judgment of acquittal and for a new trial. He also appeals the district
court’s drug quantity findings and denial of a two-level reduction for a mitigating role
in the offense. The Government cross-appeals both sentences, challenging the district
court’s variances based solely on its rejection of the 100:1 ratio.


II.   DISCUSSION


      A.     Ross’s Motion to Suppress


       Ross contends that the inculpatory statements that he made to law enforcement
should be suppressed as involuntary. On suppression issues, we review a district
court’s factual findings for clear error and its legal conclusions de novo. United States
v. Williams, 

, 1117 (8th Cir. 2005). “A statement is involuntary when
it was extracted by threats, violence, or express or implied promises sufficient to
overbear the defendant’s will and critically impair his capacity for self-determination.”
United States v. LeBrun, 

, 724 (8th Cir. 2004) (en banc), cert. denied,

(2005). In determining the voluntariness of a confession, we examine
the totality of the circumstances. 

affirm the denial of a motion to
suppress “unless the decision is unsupported by substantial evidence, is based on an
erroneous view of the applicable law, or in light of the entire record, we are left with
a firm and definite conviction that a mistake has been made.” United States v. Vega-
Rico, 

, 979 (8th Cir. 2005) (quoting United States v. Hernandez-


                                          -5-
Hernandez, 

, 564-65 (8th Cir. 2004)), cert. denied, --- U.S. ---, 

(2006).


       At the suppression hearing, Officer Logan Wernet testified that Ross initiated
the interview with the police by requesting to speak with them. After the officers gave
him oral Miranda1 warnings, Ross continued to agree to speak with them. Officer
Wernet testified that Ross wanted to cooperate, apparently in an effort to help himself.
Officer Wernet conceded that it was “entirely possible” that they told Ross that they
would forward his request to cooperate to federal prosecutors. Nevertheless, Officer
Wernet testified that he did not observe any signs that Ross’s statements were not
provided voluntarily and that Ross appeared neither upset nor agitated. Ross argues
that he was depressed and under the influence of anti-depressant medication, though
he failed to present any competent evidence establishing these facts.2 He also argues
that the officers’ agreement to involve federal prosecutors led him to believe that he
would receive leniency for his cooperation.


       Even assuming that the officers in fact promised to forward Ross’s information
to federal prosecutors, there is no evidence that such a promise overbore his will and
critically impaired his capacity for self-determination. A promise of this kind, without
more, is not enough by itself to render Ross’s statements involuntary. See United
States v. Otters, 

, 318 (8th Cir. 1999) (collecting cases); see also 

(ruling that even if a defendant’s confession was induced by a
promise, there must still be evidence that the authorities overbore defendant’s will and
capacity for self-determination). Without any evidence establishing that the officers
overbore his will and critically impaired his capacity for self-determination, Ross’s



      1
       See Miranda v. Arizona, 

(1966).
      2
      Ross’s evidence consisted solely of an undated prescription for anti-depressant
medication. He did not testify.

                                          -6-
arguments fail. We therefore affirm the district court’s denial of Ross’s motion to
suppress his statements.


      B.     Judon’s Motion for Judgment of Acquittal


       Judon contends that the evidence was insufficient to support his conspiracy
conviction. We review a district court’s denial of a motion for judgment of acquittal
de novo. United States v. Peters, 

, 957 (8th Cir. 2006). “When
reviewing the sufficiency of the evidence to support a conspiracy conviction, we will
affirm if the record, viewed most favorably to the government, contains substantial
evidence supporting the jury’s verdict, which means evidence sufficient to prove the
elements of the crime beyond a reasonable doubt.” United States v. Lopez, 

, 1030 (8th Cir. 2006) (en banc), cert. denied, --- U.S. ---, 

(2006).
To prove a conspiracy under 21 U.S.C. § 846, the Government must show that the
defendant “(1) had an agreement to achieve an illegal purpose, (2) knew of the
agreement, and (3) knowingly became part of the agreement.” United States v.
Winston, 

, 866 (8th Cir. 2006). “Direct evidence of an explicit agreement
is not necessary to prove a conspiracy; instead, a tacit understanding among co-
conspirators may be, and often will be, inferred from circumstantial evidence.” 

omitted). Indeed, “conspiracies seldom lend themselves to proof
by direct evidence.” United States v. Hoelscher, 

, 1533 (8th Cir. 1990).
Judon asserts that the evidence at trial was insufficient to establish that an agreement
to achieve an illegal purpose existed.


       The Government presented sufficient direct and circumstantial evidence to
establish the existence of an agreement between Judon and Ross. Davis Jr. testified
that on one occasion when he contacted Ross by telephone to buy cocaine, Ross
directed him to purchase it from Judon. On another occasion, Davis Jr. sought to
purchase $200 worth of crack cocaine from Ross. Ross sold Davis Jr. nine rocks of
crack cocaine for $180 and instructed Davis Jr. to purchase a tenth rock from Judon

                                          -7-
for $20, which he did. Davis Sr. testified that both Ross and Judon were present at
three of the four controlled purchases that he made. At one of those buys, Davis Sr.
purchased five rocks of crack cocaine from Ross for $100, two of which Judon
provided. When viewed in a light most favorable to the verdict, the Davises’
testimony shows that Judon and Ross had, at a minimum, a tacit agreement to
distribute crack cocaine. This evidence is therefore sufficient for a reasonable jury to
have concluded beyond a reasonable doubt that an agreement existed between Ross
and Judon to distribute cocaine.


      C.     Ross’s and Judon’s Motions for New Trials


       We review a district court’s disposition of a motion for a new trial for an abuse
of discretion. 

. Where, as here, the motions assert that the
verdicts are contrary to the weight of the evidence, “the [district] court need not view
the evidence in the light most favorable to the government, but may instead weigh the
evidence and evaluate for itself the credibility of the witnesses.” United States v.
Huerta-Orozco, 

, 565 (8th Cir. 2001). The district court should grant the
motion if the evidence weighs so heavily against the verdict that the district court
believes that a miscarriage of justice may have occurred. 

clear and
manifest abuse of discretion, we uphold the district court’s ruling on a motion for a
new trial.” 

(internal quotation omitted).


      In seeking new trials, both Ross and Judon argue that but for the testimony of
the Davises, no evidence supports their convictions, and they invite us to assess the
credibility of the Davises. Judon also argues that he should receive a new trial
because the district court erred in limiting cross-examination into the circumstances
surrounding Davis Jr.’s prior conviction, primarily focusing on the district court’s
decision to exclude evidence of the sexual nature of that conviction.




                                          -8-
       While Ross and Judon present reasonable arguments challenging the credibility
of the Davises, the Davises’ testimony was corroborated by testimony from three
Mason City police investigators and an F.B.I. agent. The Government also presented
audio recordings of some of the controlled purchases, further corroborating the
Davises’ testimony. The district court was well-positioned to assess the Davises’
credibility in making its rulings on both new trial motions. See United States v. Gabe,

, 961 (8th Cir. 2001) (declining to second-guess the district court’s
evaluation of witness credibility on a motion for a new trial). We see no abuse of
discretion in the district court’s determination that sufficient evidence supported the
jury verdicts against Ross and Judon.


       Judon also argues that the district court erred by limiting cross-examination of
Davis Jr. We review a district court’s decision to limit cross-examination for a clear
and prejudicial abuse of discretion. United States v. Haskell, 

, 1072
(8th Cir. 2006). Judon asserts that the district court erred by excluding evidence of
the sexual nature of Davis Jr.’s conviction. In United States v. Ford, 

,
1103 (8th Cir. 1994), we upheld an identical limitation in nearly identical
circumstances, holding that it was not a clear and prejudicial abuse of discretion for
the district court to exclude evidence regarding the sexual nature of the Government’s
primary witness’s conviction. 

Judon also argues that the district court
erred by limiting inquiry into the timing of Davis Jr.’s custody on the sexual assault
charge relative to his cooperation and into the circumstances surrounding his
subsequent plea. However, Judon does not identify in his briefs, nor does the record
reflect, how the district court’s limitation of cross-examination into these matters
prejudiced him. Therefore, we conclude that the district court did not clearly and
prejudicially abuse its discretion when it limited Judon’s cross-examination of Davis
Jr.


      The district court did not abuse its discretion in finding that sufficient evidence
supported the jury verdicts, and it did not abuse its discretion in limiting cross-


                                          -9-
examination into the circumstances surrounding Davis Jr.’s prior conviction. We
therefore affirm the district court’s denials of Ross’s and Judon’s motions for new
trials.


      D.     Sentencing


       We review a district court’s interpretation and application of the guidelines de
novo, its factual findings for clear error, and any decision to depart from the
appropriate guidelines range for abuse of discretion. United States v. Mashek, 

, 1017 (8th Cir. 2005). We review a district court’s decision to grant a
§ 3553(a) variance for reasonableness, 

that is akin to abuse of discretion
review. United States v. Maloney, 

, 667 (8th Cir. 2006). Ross and Judon
both challenge the district court’s drug quantity findings. Judon also asserts that the
district court erred by failing to find that he was a minor participant in the criminal
activity. The Government appeals the district court’s decision to vary from the
guidelines by using a 20:1 ratio of crack to powder cocaine instead of the 100:1 ratio
provided for in the guidelines.


             1.     Drug Quantity Findings


       We review a district court’s drug quantity findings for clear error. United States
v. Allen, 

, 452 (8th Cir. 2006), cert. denied, --- U.S. ---, 

(2006). “[W]e will reverse a determination of drug quantity only if the entire record
definitely and firmly convinces us that a mistake has been made.” 

States v. Coleman, 

, 902 (8th Cir. 1998)). At sentencing, a district court
may base factual findings on a defendant’s admissions in a proffer interview. See
United States v. Ingles, 

, 409 (8th Cir. 2005). Further,




                                          -10-
      [t]he trial court is entitled to estimate drug quantities where the amount
      actually seized fails to represent the scale of the offense if the
      preponderance of the evidence supports the quantities. The court may
      make a specific numeric determination of quantity based upon imprecise
      evidence, so long as the record reflects a basis for the court’s decision.

United States v. Roach, 

, 413-14 (8th Cir. 1998) (citations omitted). At
sentencing, it is the Government’s burden to prove drug quantities attributable to a
defendant by a preponderance of the evidence. United States v. Marshall, 

, 894 (8th Cir. 2005).


                   a.     Ross


      Ross challenges the district court’s drug quantity findings and asserts that the
Government failed to prove the amount of crack and powder cocaine attributable to
him. The district court found Ross responsible for 396.48 grams of crack cocaine and
396.48 grams of powder cocaine. The district court based its findings on evidence
presented at the sentencing hearing of Ross’s admissions during a proffer interview
with the Government in April 2005 . The notes recorded from that interview state,
“Ross estimated that he bought and sold approximately a quarter ounce of cocaine
(both powder and rocked) once a week for approximately 14 continuous months
(September of 2003 - November of 2004.)” The district court read these admissions
conjunctively, attributing to Ross the purchase and sale of a quarter ounce of crack
cocaine and a quarter ounce of powder cocaine per week.3 Ross objects to this
reading, emphasizing that the report states that “he bought and sold approximately a
quarter ounce of cocaine . . . once a week” (emphasis added).




      3
       As noted in the presentence investigation report, a quarter ounce (7.08 grams)
multiplied by 56 weeks (approximately 14 months) equals 396.48 grams.

                                        -11-
     Officer David Tyler was one of two officers present at Ross’s proffer interview.
During Ross’s sentencing hearing, Officer Tyler testified:


      Q.     Did [Ross] summarize approximately the time period that he was
             involved in selling cocaine, both powder and rock cocaine?
      A.     Yes. He said basically from August of ‘03 to November of ‘04.
      Q.     And did he say how often he sold – what kind of quantities he
             sold over the course of a week for those continuous 14, 15
             months?
      A.     He said he purchased about a quarter gram – a quarter ounce per
             week on the average over that time period.
      Q.     When you say purchased, you mean bought and sold or just
             purchased and used?
      A.     Bought and sold.
      Q.     And was that powder and – was that powder cocaine, crack
             cocaine, or both?
      A.     Both.

Transcript of Sentencing at 5.


       Officer Tyler’s testimony and the notes from Ross’s proffer are ambiguous
because they both support two different but reasonable readings. Ross reads this
evidence to state that he admitted to trafficking only in one quarter ounce of cocaine
per week during the relevant time period. The district court interpreted the evidence
to mean that Ross trafficked in both a quarter ounce of crack cocaine and a quarter
ounce of powder cocaine each week during the relevant time period. “Where there are
two permissible views of the evidence, the factfinder’s choice between them cannot
be clearly erroneous.” Anderson v. City of Bessemer City, 

, 574 (1985).
Although we recognize the ambiguity and may well have agreed with Ross if we were
reviewing this issue de novo, the entire record here does not “definitely and firmly”

                                        -12-
convince us that the district court made a mistake in interpreting the testimony and
calculating the quantity of drugs attributable to Ross. The district court’s findings are
therefore not clearly erroneous.


                    b.     Judon


        Judon also challenges the district court’s drug quantity findings. The court
attributed a total of 19.53 grams of crack cocaine to him. In reaching this amount, the
district court found Judon responsible for two sales of crack cocaine to Davis Jr.: 2.28
grams on October 22, 2004 and 2.25 grams on October 26, 2004. The district court
next attributed an additional five grams of crack cocaine to Judon on the conspiracy
charge, even though the jury specifically found Judon responsible for less than five
grams of crack cocaine in the conspiracy. Because a district court makes drug
quantity findings using a preponderance of the evidence standard when applying the
sentencing guidelines, it is not bound by the jury’s quantity findings. See United
States v. McKay, 

, 1094 (8th Cir. 2005), cert. denied, --- U.S. ---, 

(2006), and --- U.S. ---, 

(2006). The district court then
found Judon responsible for an additional ten grams of crack cocaine. Davis Jr.
testified that before he began making controlled purchases in cooperation with the task
force, he purchased crack cocaine from Judon on approximately ten occasions. On
each occasion, he purchased anywhere from one gram up to an eighth of an ounce
(3.54 grams) of cocaine. Judon argues that the district court’s finding of the ten
additional grams of crack cocaine was based on Davis Sr.’s testimony. The
sentencing transcript is ambiguous about whose testimony the district court was
actually crediting in attributing the additional ten grams of crack cocaine to Judon, but
it is clear that Davis Jr.’s testimony in fact supports this finding. The finding itself
therefore was not clearly erroneous. See 

.


       Judon also argues that the district court double-counted by attributing to him
the 2.28 and 2.25 grams from the October transactions as well as the five grams on the

                                          -13-
conspiracy count. Even if we agreed, such an error would be harmless because
removing the additional five grams from the total of 19.53 grams of crack cocaine
attributed to Judon would not change Judon’s ultimate advisory guidelines range. See
U.S.S.G. § 2D1.1(c)(7) (correlating a base offense level of 26 to at least five grams
but less than 20 grams of cocaine base). On this issue, there is no prejudicial error in
the district court’s drug quantity findings for Judon.


              2.     Judon’s Role in the Offense


       The district court also denied Judon’s request for a two-level reduction for
being a minor participant in the offense under § 3B1.2 of the guidelines. We review
a district court’s decision on a request for a mitigating role reduction for clear error.
United States v. Salazar, 

, 848 (8th Cir. 2006). A minor participant is
one “who is less culpable than most other participants, but whose role could not be
described as minimal.” U.S.S.G. § 3B1.2(b) cmt. n.5. It is the defendant’s burden to
show that he was a minor participant. See 

. “The propriety
of a downward adjustment is determined by comparing the acts of each participant in
relation to the relevant conduct for which the participant is held accountable and by
measuring each participant’s individual acts and relative culpability against the
elements of the offense.” 

on Judon’s request, the district court noted its familiarity with the trial
of the case and stated, “The role [of Judon] was less than Mr. Ross but not
substantially less in order to warrant a reduction for role in the offense.” Transcript
of Sentencing at 30. The testimony presented by the Government demonstrated that
the Davises occasionally obtained drugs from Judon after being referred to him by
Ross. On several occasions, Judon supplied drugs to the Davises when Ross had
insufficient quantities. Though Ross may have been directly responsible for supplying
more drugs, a fact accounted for by the district court’s calculation of their base offense
levels, Judon points to no evidence showing that he was less culpable than Ross in

                                           -14-
distributing the amounts of cocaine actually attributed to him. See 

. The district court therefore did not clearly err in denying Judon’s request for
a mitigating role reduction.


             3.     Crack and Powder Cocaine Disparity


      Finally, in the course of sentencing both Ross and Judon, the district court
expressly relied on United States v. Perry, 

(D.R.I. 2005), to reject
the guidelines 100:1 ratio and apply a 20:1 ratio in treating crack cocaine relative to
powder cocaine. In both cases, the district court applied what it described as a
“Booker variance” under 18 U.S.C. § 3553(a) to recalculate each defendant’s base
offense level based solely upon a 20:1 ratio.


       We recently addressed this issue in United States v. Spears, 

(8th
Cir. 2006) (en banc). There, as here, the district court categorically rejected the 100:1
crack-to-powder cocaine ratio in favor of a 20:1 ratio, also expressly relying upon the
logic of Perry.4 

The holding of Spears is straightforward: “neither
Booker nor § 3553(a) authorizes district courts to reject the 100:1 quantity ratio and
use a different ratio in sentencing defendants for crack cocaine offenses.” 

We hold that the district court here abused its discretion and committed reversible
error when it varied under § 3553(a) based solely on its rejection of the 100:1 drug
quantity ratio between crack and powder cocaine. Accordingly, we vacate the
sentences of both Ross and Judon.




      4
      The First Circuit’s ruling in United States v. Pho, 

(1st Cir. 2006),
abrogated Perry on this issue. 

n.5.

                                          -15-
III.   CONCLUSION


        For the foregoing reasons, we affirm the district court’s orders denying Ross’s
suppression motion, Judon’s motion for judgment of acquittal, and Ross’s and Judon’s
motions for new trials. Because the district court improperly varied based solely on
its rejection of the 100:1 crack-to-powder ratio prescribed by the guidelines, we vacate
the sentence of each defendant and remand to the district court for resentencing in a
manner consistent with this opinion.


                        ______________________________




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