UNITED STATES COURT OF APPEALS

FOR THE FIFTH CIRCUIT

 

No. 95-20885

 

UNITED STATES OF AMERICA, 

 

 Plaintiff-Appellee

VERSUS

 EDWARD JOHN JOHNSTON, III,

 DARRELL WAYNE ADAMS,

 ERIC DARNELL LOWERY,

 LARRY J. HILL, AND

 GONZALO J. ALVARADO 

 Defendants-Appellants

 

Appeals from the United States District Court

for the Southern District of Texas

 

October 27, 1997

Before POLITZ and KING, Circuit Judges, and DUPLANTIER*, District

Judge.

DUPLANTIER, District Judge:

 In this case involving a large scale, long term narcotics

operation, defendants-appellants Edward Johnston, Darrell Adams,

Eric Lowery, Larry Hill, and Gonzalo Alvarado appeal their

convictions on a gallimaufry of grounds. In addition, Lowery,

Johnston and Hill challenge their sentences. We affirm the

 

* District Judge of the Eastern District of Louisiana, sitting by

designation.
 

1 Mark Adams, Felicia Lowery, Angie Tubbs, Mary Veal, and A.D.

Ernest were indicted as co-conspirators. The judge granted Mary

Veal's motion for mistrial. During the trial A.D. Ernest entered

a plea of guilty. Mark Adams and Felicia Lowery were acquitted by

the jury. The jury was unable to reach a verdict as to Angie Tubbs.

2

convictions except as follows: we reverse and remand for further

proceedings as to Larry Hill's only conviction (count 1) and as to

Darrell Adams' conviction of count 15. We affirm the sentences

challenged by Lowery and Johnston.

 PROCEDURAL HISTORY

 The final superseding indictment upon which the government

proceeded to trial charged the five appellants and five other

individuals1 with conspiracy (count 1) to possess with intent to

distribute in excess of five kilograms of cocaine, fifty (50) grams

or more of a mixture containing cocaine base, and 100 kilograms or

more of marihuana, in violation of 21 U.S.C. 841(a)(1),

841(b)(1)(A)(ii) and (iii), 841(b)(1)(B)(vii), and 846.

 Darrell Adams was also charged with five counts of possessing

cocaine with intent to distribute in violation of 21 U.S.C.

841(a)(1), 841(b)(1)(A)(ii) and 18 U.S.C. 2 (counts 2, 4, 6, 7, and

8), one count of possessing cocaine base with intent to distribute

in violation of 21 U.S.C. 841(a)(1) and 841(b)(1)(A)(ii) & (iii),

and 18 U.S.C. 2 (count 3), five counts of possessing marijuana with

intent to distribute in violation of 21 U.S.C. 841(a)(1) and

841(b)(1)(D) and 18 U.S.C. 2 (counts 5, 9, 10, 11, and 12), one

count of conspiracy to commit money laundering in violation of 18

U.S.C. 1956(a)(1)(A)(i), 1956(a)(1)(B)(i), 1956 (g), and 18 U.S.C.
3

371 (count 14), and one count of using and carrying a firearm in

relation to a drug trafficking crime in violation of 18 U.S.C.

924(c) (count 15). 

 In addition to the conspiracy count Alvarado was indicted on

three counts of possessing cocaine with intent to distribute

(counts 2, 6, and 7), and two counts of possessing marihuana with

intent to distribute (counts 5 and 12). 

 The trial lasted approximately eight weeks. The district

judge granted Adams' motion for directed verdict on one count of

possessing marijuana with intent to distribute (count 11).

Following several days of deliberations, the jury convicted all of

the appellants on the conspiracy count. Adams was also convicted

on four counts of possessing cocaine with intent to distribute, one

count of possessing cocaine base with intent to distribute, two

counts of possessing marihuana with intent to distribute, one count

of conspiracy to commit money laundering, and one count of using

and carrying a firearm in relation to a drug trafficking crime.

The jury acquitted Adams on one count of possessing cocaine with

intent to distribute (count 4) and two counts of possessing

marihuana with intent to distribute (counts 9 and 12). Alvarado

was convicted on all counts on which he was indicted. 

 Appellants were sentenced as follows: 

 • Johnston, imprisoned for 135 months and a five year term

 of supervised release.

 • Adams, concurrent terms of life imprisonment

 on counts 1, 3, 7 and 8; 60 months on counts 5 and
4

 10, and 240 months on counts 2 and 14, each of those 

 sentences to run concurrently, and a 60 month consecutive 

 term of imprisonment on count 15 (the gun count), 

 concurrent terms of supervised release, and a $25,000 fine.

 • Lowery, imprisonment for 360 months, a five year term of

 supervised release, and a $10,000 fine. 

 • Hill, imprisonment for 72 months, a three year term of 

 supervised release, and a $6,000 fine.

 • Alvarado, concurrent terms of imprisonment of 340 

 months, 240 months and 60 months, concurrent terms of 

 supervised release, and a $20,000 fine.

EVIDENCE

 At the heart of this case is a widespread conspiracy to

possess with intent to distribute marijuana, cocaine base, and

cocaine, which operated from 1989 until 1994. Members of the

conspiracy obtained large amounts of marijuana and cocaine in

Houston, Texas and transported the drugs to Shreveport, Louisiana

for distribution. 

 The government's case relied heavily upon the testimony of

various participants in the conspiracy, including unindicted coconspirators and indicted co-conspirators who entered into plea

agreements with the government. Numerous law enforcement personnel

and other witnesses also testified. Because of the nature of the

errors urged by appellants, an extensive recitation of the evidence

is necessary. We first review the evidence generally, as

background for discussion of meritless claims of error by the
 

2 Ultimately, Cash entered into a plea agreement with the

government; he pleaded guilty to a single count of "using and

carrying" a gun in relation to a drug trafficking crime in

violation of 18 U.S.C. §924(c).

5

district court and of prosecutors' misconduct. Concluding that

some of the other misconduct claims are justified, we then discuss

the effect thereof upon the convictions. 

 On December 3, 1991, Bosia Cash was stopped by a Diboll, Texas

constable for a traffic violation. After seeing a gun in the

vehicle and hearing Cash and his passenger Diane Mitchell give

inconsistent accounts of their trip, the constable conducted a

consensual search of the car and discovered three kilograms of

cocaine. The constable arrested Cash and contacted John Marshall,

a Shreveport DEA agent. Thereafter Cash agreed to cooperate with

the DEA.2 Agent Marshall and Cash attempted to arrange a controlled

delivery of the cocaine to Roosevelt Wisener in Shreveport;

however, the attempt was unsuccessful. Cash then attempted to

telephone appellant Adams. When Adams returned Cash's call, in a

recorded conversation he told Cash that Cash was responsible for

"them people's cocaine." 

 Thereafter, with the cooperation of Cash, DEA agent Robert

Mansaw, acting in an undercover capacity, attempted to purchase

several kilograms of cocaine from Adams. Adams failed to appear

for a scheduled meeting with Mansaw, sending Roosevelt Gatterson,

an unindicted co-conspirator, in his place. A purchase of cocaine

was ultimately arranged, but the deal was never consummated. In

recorded telephone conversations Mansaw and Adams discussed the
6

price of cocaine, and Adams told Mansaw that he would make sure

Mansaw got his "package."

 At trial Cash identified Adams, a resident of Houston, as his

source of the three kilograms of cocaine he was transporting at the

time he was arrested and of other cocaine he had previously

obtained. Cash described a prior transaction in which he delivered

two kilograms of cocaine received from Adams to Danzel Morris.

Morris refused to pay Cash for the cocaine, stating that Adams owed

him cocaine. Adams told Cash that he owed Adams for the lost

cocaine. Cash later gave Adams a race car and a truck as payment

for the cocaine. Adams told Cash that his source for cocaine was

an individual known as "Charlie", whom Cash and several other

witnesses identified as appellant Alvarado.

 Adams introduced Cash to Stevenson McClendon and Roosevelt

Gatterson. McClendon worked with Adams at the Port of Houston. In

a separate case, McClendon entered into a plea agreement in which

he agreed, inter alia, to testify in this case. McClendon

testified that he introduced Adams and Alvarado in 1989, that in

1990 he bought kilogram quantities of cocaine for Adams from

Alvarado, and that he made two trips to Shreveport to deliver

cocaine for Adams, on each occasion delivering two to three

kilograms of cocaine to Cash. McClendon also testified that he

witnessed Adams giving Alvarado money.

 Gatterson also cooperated with the government and testified

as follows. After Adams bought ProCare Engine Exchange

(ProCare), an engine installation business in Houston, Gatterson
7

worked there for approximately a year. In 1992 he picked up

marijuana several times for Adams and delivered it to Shreveport,

in vehicles belonging to Adams. Gatterson also delivered marijuana

for Adams to Bruce Embrey and delivered kilogram quantities of

cocaine to Shreveport for Adams, some of it to Cash. "Charlie"

(Alvarado) provided Adams with the drugs. At Adams' request

Gatterson picked up a tire containing cocaine from the side of

Alvarado's house and delivered it to the barn where Adams' horses

were stabled. Gatterson counted large amounts of cash at Adams'

house on at least six occasions. At times while transporting drugs

for Adams, Gatterson carried a gun provided by Adams.

 In approximately May 1992 Albert Smith, then shop foreman at

ProCare, arrived at ProCare early one morning and witnessed

Gatterson and another man identified as Frank weighing white powder

in the break room. Smith testified that he also saw the two men

putting two packages of white powder in each of three tire rims.

Several days after this incident, Adams required Smith to

relinquish his keys to the ProCare building.

 Kimela Lomax was paid for information provided to Agent Mansaw

and testified for the government. She dated Adams for a number of

months during the conspiracy and worked at ProCare after it was

purchased by Adams. Lomax accompanied Adams on several trips to

Shreveport, where Adams "took care of business" (his drug

business). During these trips Adams met with appellants Lowery and

Johnston. On several of these trips to Shreveport, Adams returned

to Houston with large amounts of money. After Lomax and Adams
8

returned from one trip to Shreveport, Lomax and Gatterson helped

Adams count more than $100,000. 

 Johnston delivered money to Adams' house in Houston twice

while Lomax was present. Following one delivery of money by

Johnston, Lomax helped count $90,000. Adams informed Johnston that

the money was "short." Thereafter Johnston called Lowery, and Adams

advised Lowery that they would be "minus one." Lomax testified

"minus one" meant one kilo. 

 Adams told Lomax that "Charlie" was the source of his cocaine.

In August 1993, Lomax and Adams went into hiding because they

feared that their lives and those of Alvarado's family were in

danger due to a delay in receiving money from Shreveport. 

 Bruce Embrey, an indicted co-conspirator who entered into a

plea agreement with the government, worked at the Port of Houston

and met Adams between 1989-1991. He testified that he purchased

marijuana from Adams on several occasions and delivered that

marijuana to Roy Patterson and A.D. Ernest, among others. Ernest

was later employed by Adams at ProCare. After Adams purchased

ProCare he asked Embrey to obtain kilogram quantities of cocaine.

Embrey arranged for Adams to purchase two kilograms of cocaine from

Sam Nash. Adams paid Nash the $28,000 purchase price, but the

boxes delivered to Adams did not contain cocaine. Adams told

Embrey that Embrey owed Adams for the loss. Thereafter, Embrey

transported cocaine to Shreveport for Adams on two occasions, and

on two occasions Embrey secreted cocaine in tires at Adam' request.

On the second occasion Embrey put ten kilograms of cocaine into a
9

tire. 

 Roy Patterson, an unindicted co-conspirator, testified that he

transported cocaine and marijuana from Houston to Shreveport for

Adams. He stated that in May 1993, Lowery and Johnston appeared at

the ProCare office. After Adams met with Lowery, Adams asked

Patterson if he wanted to make a trip to Shreveport and suggested

that Patterson talk to Lowery. Lowery asked Patterson to deliver

thirty (30) pounds of marijuana to Shreveport. According to

Patterson he agreed to make the trip, and Lowery gave him the

number to call when he reached Shreveport. Johnston placed a bag

in Patterson's trunk, which Patterson said he left at Lowery's

house in Shreveport. Shortly thereafter Adams asked Patterson to

make a second trip to Shreveport. Patterson testified that he

picked up five (5) kilograms of cocaine from "Charlie" at the

stables where Adams kept his horses, delivered the cocaine to

Lowery, returned to Houston with $190,000 in cash given to him by

Lowery, and delivered the cash to Adams at his home.

 Patterson also testified about a second delivery of thirty

(30) pounds of marijuana which he made shortly after that cocaine

delivery. Patterson delivered the marijuana to Lowery, who then

phoned appellant Hill. Patterson testified that within a few

minutes Hill joined him and Lowery. Patterson brought the

marijuana to the home of Jennifer Gerard, Lowery's sister and

Hill's girl friend at the time. Hill unlocked the door and

Patterson brought the marijuana into the house. Patterson

testified that he, Lowery, and Hill weighed the marijuana. 
 

3 The testimony of the two Pattersons about this one incident

is the only evidence of participation by Hill in the conspiracy for

which he was convicted.

10

 Patterson testified about numerous other trips to Shreveport

to deliver cocaine and marijuana, generally returning to Houston

with large amounts of cash which he delivered to Adams. It was not

uncommon for Patterson to transport six or more kilograms of

cocaine on each trip. Patterson also testified that he accompanied

Johnston on one trip to Shreveport to deliver marijuana to Lowery.

On another occasion Patterson delivered to Edward Johnston in

Houston four kilograms of cocaine ultimately destined for

Shreveport. Patterson also assisted Adams in counting large sums

of money several times.

 On January 15, 1994, while transporting sixty (60) pounds of

marijuana at Adams' request to Shreveport for delivery to Lowery,

Roy Patterson was stopped and arrested. The marijuana was seized.

 Derrick Patterson, Roy Patterson's son, testified that he

accompanied his father on some trips to Shreveport and corroborated

his father's testimony concerning several of the trips, including

the testimony that Hill weighed the bundles of marijuana Patterson

delivered on one trip.3 After a trip to Shreveport, at Adams'

request Derrick Patterson drove Adams' vehicle containing more than

$300,000 cash back to Houston, where he delivered the money to

Adams. He also witnessed Adams deliver cash to Alvarado; at ProCare

he answered telephone calls from Johnston and Lowery for Adams. 

 Officer Henry King of the Shreveport police testified that

while acting in an undercover capacity he purchased cocaine base,
11

sometimes referred to as "crack", from George Robinson, an indicted

co-conspirator who entered into a plea agreement with the

government. King discussed with Robinson the possibility of

purchasing large quantities of cocaine. Robinson told King that

his source for cocaine was in Houston, identified Adams as the

source, and gave King Adams' phone number. King made several

attempts to set up a deal with Adams; however, no deal was ever

consummated.

COMMENT BY THE DISTRICT JUDGE

 Roy Patterson, a convicted felon on probation during the time

covered by the conspiracy, was cross-examined extensively by two

defense counsel concerning his failure to comply with some

conditions of his probation, e.g., using drugs and lying to his

probation officer. Following those cross examinations, another

defense attorney asked Patterson if he "ever [told] the probation

officers and the drug counselors how much admiration you had for

all the work they'd done for you?" The government objected to the

question on the grounds of relevance and materiality. The judge

stated:

 [t]he objection has been sustained. We've had a 

 lot of examination about this man's probation and

 his failure to adhere to what he was supposed to

 do and the way he didn't disclose it to the probation

 officer. That's all well before the jury. I think we 

 can get on to what the case is about.

 

(23 R. 37). Defendants moved for a mistrial; the motion was

denied.

 Adams, Johnston and Lowery contend that the district judge's

statement deprived them of a fair trial because it eviscerated
12

their defense that the government's witnesses were not credible. 

 In determining whether a judge has exceeded the bounds of

acceptable conduct, the proceedings must be viewed as a whole.

United States v. Dobbs, 63 F.3d 391, 398 (5th Cir. 1995). The

critical inquiry is "whether the judge's behavior was so

prejudicial that it denied [the appellants] a fair, as opposed to

a perfect trial." United States v. Williams, 809 F.2d 1072, 1086

(5th Cir. 1987), cert. denied 484 U.S. 896, 108 S.Ct. 506, quoting

United States v. Pisani, 773 F.2d 397, 402 (2nd Cir. 1985). 

 Appellants' claim is without merit; the judge's comment did

not deny Adams, Lowery, and Johnston a fair trial. Following the

judge's statement, the cross examination of Patterson continued for

a short while. Then the trial recessed for a lunch break. When the

trial recommenced, the judge immediately instructed the jury as

follows:

 Somewhere about a quarter an hour before we recessed

 at one point in time when objections had been made to

 examination -- cross examination being conducted by 

 Mr. Gerson that were sustained, I made a remark, 

 "Let's move along to what the case is about or something

 like that.

 I do not want you to take that remark as any indication

 that the case is not also about the credibility of

 witnesses because it always is. And, of course, as Mr.

 Gerson went on to do for some time, he asked a number of

 questions that bore upon the credibility of the witness

 he was cross-examining.

 As I will instruct you at the end of the case, one of the

 duties of the jurors will be to decide the credibility, 

 which witnesses to believe, which witnesses not to 

 believe, how much of each witness's testimony to believe,

 how much not to believe. That will all be part of the 

 instructions at the end of the case.

 Certainly I did not mean to indicate to you at the
13

 time of that ruling by any offhand remark that 

 credibility of witnesses is not important. It is and

 its a proper area for cross-examination.

(23 R. 3751).

 This timely instruction stressed the importance of the

credibility of witnesses and informed the jury that it was their

duty to determine credibility. Additionally, at the conclusion of

the trial the judge instructed the jury that "[a]n important part

of your job will be making judgments about the testimony of

witnesses. You should decide whether you believe what each person

had to say and how important that testimony was." (40 R. 8177).

The judge also told the jury that "[e]xcept for the instructions to

you on the law and these instructions, of course, you should

disregard anything I may have said during the trial in arriving at

your own findings as to the facts." (40 R. 8176). These

instructions amply guarded the appellants against any prejudice

resulting from the district judge's statement. 

LIMITATION OF CROSS EXAMINATION

 Lowery, Adams and Johnston assert that the district court

committed reversible error by restricting the cross examination of

Robert Mansaw concerning inconsistencies between his testimony and

that of Roy Patterson. Appellants urge that the limitation denied

them their Sixth Amendment right to confront their accusers.

Limitations on the scope of cross-examination are reviewed for

abuse of discretion. United States v. Route, 104 F.3d 59, 64 (5th

Cir.), cert. denied, U.S. , 117 S.Ct. 2491 (1997). 

 Agent Mansaw was asked if when he spoke with Roy Patterson on
14

February 7, 1995, Patterson mentioned the name Larry Hill. Mansaw

replied, "[y]es, he did." Defense counsel then asked "[s]o if he

told the jury that he did not, that would have been an untruthful

bit of testimony by Roy Patterson. Is that what you want to say?"

(36 R. 7191). The government objected to the question on the basis

that it was improper impeachment in that it called for an opinion.

The objection was sustained. The following colloquy ensued:

 MR. ACKERMAN: Your honor, I'm not trying

 to prove what Mr. Patterson said to the jury. I am 

 confronting this witness with a prior statement.

 THE COURT: That's going to be up to the jury to 

 decide whether the witness testified truthfully or

 not.

 MR. ACKERMAN: Your Honor, I'm not asking it in the 

 form of a hypothetical, "If he so testified, would 

 that have been true? I agree that it's up to the jury

 to decide whether that's what he said.

 THE COURT: I'll sustain the objection.

 MR. ACKERMAN: Okay. Your Honor, the Constitution of 

 the United States gives me the right to confront

 witnesses called by the government.

 THE COURT: You're doing that.

 MR. ACKERMAN: And I'm being denied that right by

 limiting me in this regard and I object.

 THE COURT: Sustain this objection.

(36 R. 7191-92). 

 Defense counsel elicited testimony from Agent Mansaw that was

inconsistent with certain testimony given by Roy Patterson. It was

the jury's obligation to determine the credibility of Roy

Patterson. Agent Mansaw's opinion as to whether Patterson was

telling the truth concerning his statement on February 7 is not
 

4 Appellants do not specify which exhibits they contend were

admitted in error. They simply identify portions of the transcript

where various exhibits were offered into evidence by the

government, objected to by defendants, and then admitted into

evidence. 

15

relevant. The district judge was correct in not permitting defense

counsel to continue to pursue that line of inquiry.

ADMISSION OF RECORDS FROM PROCARE

 Appellants Lowery, Johnston and Adams contend that the

district judge erroneously admitted into evidence a large number of

what they term "` business records' of ProCare" seized from

ProCare's offices pursuant to a search warrant.4 They contend that

the proper foundation was not laid to admit the records under Rule

803(6) of the Federal Rules of Evidence, the business records

exception. We review the district court's evidentiary rulings for

abuse of discretion. United States v. Carrillo, 20 F.3d 617, 619

(5th Cir.), cert. denied, U.S. , 115 S.Ct. 261, 130

L.Ed.2d 181 (1994).

 Appellants' contention lacks merit. The records at issue are

of a business (ProCare) owned and operated by appellant Adams, not

documents of a third party, and were seized on the premises of

ProCare. As such, the documents are admissible once their

authenticity is established regardless of whether they fit the

business records exception. Authenticity is established "by

evidence sufficient to support a finding that the matter in

question is what its proponent claims." Fed. R. Evid. 901(a).

These documents were properly authenticated. Agents Timothy

Binkley and Anderson Jackson participated in the search of the
16

ProCare premises and testified concerning the circumstances under

which the documents were seized. ProCare employees Kimela Lomax

and Karen Franklin also authenticated the documents. 

 In any event, a proper foundation under Rule 803(6) was

established for the exhibits. Both Kimela Lomax and Karen

Franklin, who handled record keeping for Adams at ProCare,

testified that the documents at issue were kept in the regular

course of business and relied upon by Adams. This satisfied Fed.

R. Evid. 803(6). The district judge properly admitted the exhibits

into evidence.

PROSECUTORIAL MISCONDUCT

 All appellants contend that various acts of misconduct by the

prosecutors, viewed either individually or cumulatively, denied

them a fair trial, requiring reversal of their convictions.

Criminal defendants bear a substantial burden when they attempt to

show that prosecutorial improprieties constitute reversible error.

United States v. Bermea, 30 F.3d 1539, 1563 (5th Cir. 1994), cert.

denied sub. nom., 513 U.S. 1156, 115 S.Ct. 1113, 131 L.Ed.2d 746

(1995). "[A] conviction should not be set aside if the

prosecutor's conduct . . . did not in fact contribute to the guilty

verdict and was, therefore legally harmless." United States v.

Cardenas, 778 F.2d 1127, 1129-30 (5th Cir. 1985) (citations

omitted). 

 The acts of claimed prosecutorial misconduct range from the

frivolous to the egregious and fall into several different

categories. A careful review of the briefs, oral argument, and the
 

5 Brady v. Maryland, 373 U.S.83, 83 S.Ct. 1194, 10 L.Ed.2d 215

(1963)

 

6 Giglio v. United States, 405 U.S. 150, 92 S.Ct. 763, 31

L.Ed.2d 104 (1972).

 

7 18 U.S.C. 3500

17

trial transcript convinces us that the following complaints lack

merit and do not require further discussion: the prosecutors'

personal actions towards defense counsel, including approaching

counsel in a menacing way, calling irrelevant witnesses, addressing

defense counsel directly, physically "charging" a defense counsel

who stated an objection, referring to defense counsel as "criminal

defense counsel", and the government's breach of its plea agreement

with George Robinson, who is not an appellant here. However, each

of the following warrants detailed analysis: discovery violations,

open display of unadmitted exhibits, references to Adams' prior

conviction, improper questioning of law enforcement officers, and

comments on defendants' failure to testify. 

A. Discovery Violations

 Lowery, Adams and Johnston contend that the government

repeatedly violated the district court's discovery orders and

failed to disclose Brady5, Giglio6, and Jencks7 material in a timely

manner. Appellants do not allege any specific prejudice resulting

from the delayed productions. Rather, in general terms they

assert that they were prejudiced because the delayed disclosures

diverted defense counsels' attention "from the tasks of defending

to the task of preparing." (34 R. 6761).

 The government clearly delayed in producing a number of
18

discovery materials. At the final pretrial conference the district

judge ordered the production of Jencks material on the day before

the witness would testify. Despite that order, the government

failed to produce the tape recorded statement of Kimela Lomax or

even disclose its existence until after several defense counsel had

completed their cross examinations of Lomax. The tardy production

of the tape necessitated a postponement of Lomax's crossexamination to allow defense counsel an opportunity to review the

tape and prepare appropriate cross-examination. 

 Prosecutors did not reveal the existence of a plea

agreement with Bosia Cash prior to his direct testimony, and

contrary to the district judge's order, produced a transcript of

Cash's testimony before the grand jury only after Cash began

testifying. The government was also dilatory in producing its plea

agreement with Stevenson McClendon; the agreement was first

produced on the day he testified. 

 We disagree with appellants' complaint that a video tape of

a traffic stop involving Edward Johnston and a recorded statement

of Marilyn Timmons were produced late. The government produced the

tape of the traffic stop several days before the date that the

officer who executed the stop testified, and the tape of Timmons

several days before Timmons, who was not actually called to

testify, was scheduled to testify. 

 The record also does not support Lowery's contention that the

prosecutor did not timely disclose information concerning the

payments made by Agent Mansaw to Kimela Lomax. The prosecution did
19

timely inform defendants of the total amount of payments made to

Lomax, although the actual payment vouchers were not produced until

Lomax's cross-examination. 

 Appellants also argue that the prosecution failed to disclose

"informal immunity" agreements entered into with several witnesses,

including Derrick and Roy Patterson. In fact, there were no such

immunity agreements. Before the trial began, a prosecutor

indicated that Gatterson, Lomax, Derrick Patterson and Roy

Patterson had received "informal immunity" from agents involved in

the investigation of the case. In response to defendants' motion

to disclose the agreements, the prosecutor stated that there were

no such agreements, and that he had inferred their existence from

the fact that those witnesses had been interviewed without having

been given Miranda warnings. The agents involved were crossexamined extensively about the existence of such agreements, and

they confirmed that there were none. The government cannot disclose

that which does not exist. 

 Appellants also contend that several times the government

attempted to call witnesses to testify without giving one day's

prior notice of their appearance, contrary to the judge's orders,

and that these violations resulted in trial delays. They also

complain of a delay that ensued when the prosecution failed to

timely provide defense counsel with a copy of a summary chart.

Appellants articulate no specific prejudice due to the alleged

trial delays.

 The fact that the witnesses were not identified and materials
20

were not produced in accordance with the judge's prior orders does

not equate to prosecutorial misconduct. "The trial court holds

real latitude in the management of the discovery process, including

fashioning the appropriate remedy for alleged discovery errors."

United States v. Ellender, 947 F.2d 748, 756 (5th Cir. 1991). We

review alleged errors in the administration of the discovery

process for abuse of discretion. Id. Delayed production is not in

and of itself a ground for reversal of a conviction. Prejudice to

the substantial rights of a defendant is required before reversal

of a conviction is warranted. United States v. Garcia, 917 F.2d

1370, 1374 (5th Cir. 1990). 

 The delayed identifications and productions did not prejudice

appellants' substantial rights. We do not condone the

government's less than satisfactory compliance with the district

judge's discovery orders; however, we recognize that this was a

long and difficult prosecution. The trial began with ten

defendants and a fifteen count indictment. There were a large

number of potential witnesses and exhibits. These factors imposed

an unusually heavy administrative burden on the government, and

adversely affected the prosecutors' ability to comply with the

discovery orders. Although the district judge voiced his

displeasure concerning the prosecution's repeated failure to timely

produce discovery materials, he determined that the delays were not

intentional and did not prejudice the appellants. Our review of

the record does not persuade us otherwise.

 Moreover, the district judge, cognizant of the potential for
21

prejudice inherent in the late disclosures, postponed the

examination or cross-examination of every witness where there was

either a late disclosure of discovery materials or a failure to

timely reveal the identity of a witness who would be called. These

postponements gave defense counsel an adequate opportunity to

examine and analyze the material produced and adequately prepare a

cross-examination of the witness. Appellants did not experience

any prejudice to their substantial rights due to the prosecutors'

discovery violations. 

B. Display of Guns and Drugs

 Appellants contend that the prosecutors acted improperly at

the start of the trial by displaying on the prosecutor's table in

the plain view of the jury various drugs and weapons which had not

been admitted into evidence. Defendants timely objected to the

display. Outside the jury's presence, the judge ordered the

government not to display anything on the table that was not on the

exhibit list. The judge then instructed the jury: 

 Ladies and gentlemen, with respect to the exhibits 

 that -- or potential exhibits that are on the table,

 these are not in evidence. There's a weapon of

 some type lying out there on that table and other 

 paraphernalia. You are not to consider those for any

 purpose at this time. Those are not exhibits in 

 evidence at this time. There are no exhibits in

 evidence at this time.

 Whether those will come into evidence or not I don't 

 know. But you're going to consider in this case

 only the exhibits and you are not to be in any way

 influenced by anything that you have seen in 

 connection with materials lying on the tables of

 counsel at this time. That is not in evidence.

 We have not had any testimony. We've not had

 any exhibits at this time.
 

8 Johnston adopted this portion of Adams' brief. Because the

challenged testimony and comment do not pertain to Johnston, he

could not have experienced any prejudice. Accordingly, we limit

our discussion to Adams.

22

(12 R. 221, 236-37).

 Because neither the government nor the appellants recall

specifically what items were displayed on the table, we are unable

to determine whether all of the items displayed on the table were

later admitted into evidence. However, the record does demonstrate

that a gun and several exhibits of cocaine were admitted.

Considering the district judge's instruction to the prosecution to

remove any items which were not listed on the witness list, the

lack of a record indicating that any displayed item was not

admitted into evidence, and the judge's thorough instruction that

the items displayed were not evidence, we conclude that appellants

suffered no prejudice from the display.

C. References To Adams' Prior Convictions

 Adams contends that the prosecutors acted improperly by

intentionally eliciting testimony concerning and commenting upon

his prior criminal record, despite the fact that the judge had

granted a motion in limine prohibiting such references.8 Appellant

does not provide a record reference for either the motion or an

order granting it, and we found none in reviewing the record.

Nevertheless, assuming arguendo that such a motion was granted,

under Rule 103 of the Federal Rules of Evidence, the "plain error"

standard of review applies if at trial the defendant failed to

timely renew the objection raised by motion in limine. United
23

States v. Graves, 5 F.3d 1546, 1551 (5th Cir. 1993), cert. denied

sub. nom., 511 U.S. 1081, 114 S.Ct. 1829, 128 L.Ed.2d.459 (1994).

 Three separate incidents form the foundation for Adams'

challenge. Kimela Lomax testified that a vehicle in which she and

Adams were riding was stopped by law enforcement officials, and

that there were guns in the vehicle. She testified, without

objection, that she and Adams were charged with the offense of

carrying a weapon. On cross-examination, Lomax testified that she

pleaded no contest to the charge and received probation.

Thereafter, on redirect examination, a prosecutor asked Lomax "[w]e

know what happened to you. What happened to Darrell?" Lomax

answered, "[h]e got probation." (27 R. 5086).

 There was no objection to the question at that time, although

counsel later filed a motion for mistrial based in part on the

question concerning Adams' prior conviction. The failure of

counsel to object to the admission of the evidence at the first

available opportunity waived any ground of complaint against its

admission, absent plain error. United States v. Vesich, 724 F.2d

451, 462 (5th Cir. 1984). When a defendant has forfeited an error

by failing to object, the error is remedied only "in the most

exceptional cases." United States v. Calverley, 37 F.3d 160, 162

(5th Cir. 1994)(en banc), cert. denied, U.S. , 115 S.Ct.

1266, 131 L.Ed.2d 145 (1995). Plain error is "error so obvious

and substantial that failure to notice it would affect the

fairness, integrity, or public reputation of the judicial

proceedings and would result in manifest injustice." United States
24

v. Reyes, 102 F.3d 1361, 1364 (5th Cir.), cert. denied, U.S.

 , 117 S.Ct. 180, 136 L.Ed.2d 166 (1996). The prosecutor well

knew that the question would elicit evidence that the defendant had

a prior conviction; evidence that was irrelevant and prejudicial,

and in violation of Rule 404(b) of the Federal Rules of Evidence.

The prosecutor acted improperly in asking the question; however, we

conclude that the misconduct does not satisfy the high standard

required to qualify as plain error.

 The second incident occurred when, after Lomax's testimony

that Adams was sentenced to probation, the prosecutor asked Lomax

"[d]id you ever have conversations with Darrell Adams about his

concern" (previous questions made it clear that the prosecutor was

referring to concern about going to the penitentiary). Defense

counsel's objection was overruled. Lomax answered, "[h]e said he

wasn't worried about going back", thus telling the jury that Adams

had once before been to the penitentiary. No objection was stated

at that time.

 Because Adams did not object to the comment at the first

opportunity available, we review for plain error. Although Lomax's

response to the question of Adams' concern about going to the

penitentiary was not responsive to the question in the strictest

sense, that does not factor into our analysis because we can safely

assume that the prosecutor was indeed soliciting the answer which

the witness gave. The government's introduction of evidence that

the defendant had previously served a penitentiary term was clearly

improper, but the following court instruction alleviated the
25

resulting prejudice:

 First, I want to instruct you that I am striking one

 of the responses of Ms. Lomax that she gave in reply

 to a question yesterday. There was a question asked

 whether Ms. Lomax had conversations with Darrell

 Adams about his concern. Ms. Lomax, instead of 

 answering "yes" or "no," which would have been all 

 that the answer called for, answered with a statement

 that I'm going to instruct you to disregard entirely.

 You are not to speculate upon it at all.

 The answer was said he wasn't worried about going back.

 That answer is stricken from the record. It was an

 improper response. You are instructed to disregard it

 completely and to pay no attention to it or speculate

 upon it at all in any of your considerations about this

 case.

(28 R. 5117) The instruction was thorough, and "juries are

presumed to follow their instructions." United States v.Castillo,

77 F.3d 1480, 1491 (5th Cir.), cert. denied, U.S. , 117

S.Ct. 180 (1996). The prejudice is also mitigated by the fact that

the jury later learned from Adams himself that he had previously

been in the penitentiary. See United States v. Davis, 831 F.2d 63,

65 (5th Cir. 1987). In a taped conversation between Adams and

Robert Mansaw, Adams stated "I done been down that road . . .

penitentiary . . . and I got [sic] going back."

 Finally, Adams objects to the following portion of the

government's closing argument:

 [Roosevelt Gatterson's] been to prison for dope.

 He kind of felt that he and Darrell had a lot in

 common, that they had a lot to talk about, they

 were kind of kindred spirits, had common background.

(39 R. 7805). Adams did not object to the comment. Accordingly we

review the statement for plain error. United States v. Bermea, 30

F.3d 1539 (5th Cir. 1994), cert. denied sub. nom., 513 U.S. 1156,
26

115 S.Ct. 1113, 131 L.Ed.2d 746 (1995).

 We disagree with appellants' contention that the statement is

a direct comment on Adams' prior conviction; the "common

background" referred to could reasonably be construed as a

background in narcotics trafficking. 

D. Improper Questioning of Law Enforcement Agents

 Appellants characterize numerous questions by prosecutors to law

enforcement agents as objectionable to such an extent that,

considered together, they constitute prosecutorial misconduct. We

therefore review them as such, rather than as claimed error by the

trial court with respect to evidentiary rulings. Appellants contend

that the prosecutors intentionally and repeatedly questioned law

enforcement agents in a manner calculated to violate the

Confrontation Clause of the Sixth Amendment. By asking law

enforcement officials what steps they took during their

investigation and why they took those steps, appellants assert

that the prosecutors were able to indirectly introduce damaging

hearsay testimony of informants and law enforcement officials. They

also contend that the prosecution asked improper questions designed

to elicit irrelevant testimony which was prejudicial. 

 Rule 803 of the Federal Rules of Evidence defines "hearsay" as

"a statement, other than one made by the declarant while testifying

at the trial or hearing, offered in evidence to prove the truth of

the matter asserted." Out-of-court statements offered for another

purpose, e.g., providing background information to explain the

actions of investigators, are not hearsay. United States v.
 

9 Lowery alone cites more than one hundred fifty examples of

questions or portions of testimony which he contends are improper.

27

Carrillo, 20 F.3d 617, 620 (5th Cir.), cert. denied, U.S.

 , 115 S.Ct. 261. 130 L.Ed.2d 18 (1994), citing United States v.

Gonzalez, 967 F.2d 1032, 1035 (5th Cir. 1992). 

 "Although relevant, evidence may be excluded if its probative

value is substantially outweighed by the danger of unfair prejudice

. . .." Fed. R. Evid. 403. "The more directly an out of court

declaration implicates the defendant, the greater the danger of

prejudice." United States v. Carillo, 20 F.2d at 620. If an outof-court statement does not directly implicate the defendant, then

the probative value outweighs the prejudice. Id. Appellants

Johnston, Lowery, Hill and Adams point to numerous instances of

alleged improper questioning9; we address only those instances

where an appellant is directly implicated.

 Michael Hembree, a DEA agent, testified that he and Agent

Margaret Brice, a deputy narcotics investigator with the Caddo

Parish Sheriff's Office, interviewed Tracy Boston, who was in

custody at the Shreveport jail. The AUSA then asked Hembree:

"[c]an you tell the members of the jury what you did after you

spoke with Tracy Boston." (20 R. 2761). Defendants' objection was

overruled and Hembree answered:

 We refocused [our] investigation more narrowly

 to certain individuals and activities that were

 being conducted specifically by certain individuals

 and their part as partners in a drug organization, 

 other specific parts in that organization.

Id. When the prosecutor later asked "if [he] went any other place
28

or examined any other records or did anything other thing after

that", Hembree stated that he had a conversation with Agent Brice.

Id. The prosecutor then asked Hembree the nature of the

conversation, and Hembree replied "Eric Lowery, Felicia Metcalf

Lowery, the conversation was regarding Eric Lowery, Felicia Metcalf

Lowery and a residence located at 9469 Pitch Pine Road in

Shreveport." (20 R. 2762).

 The prosecutor's questions succeeded in demonstrating to the

jury that information conveyed to Hembree by Boston and Brice

incriminated Lowery; the information was probably inadmissible per

se, and the sources were not subject to cross examination. An

earlier effort by the prosecutor to reveal to the jury the topic of

Hembree's conversation with Boston had already been thwarted. When

the prosecutor asked Hembree about the topic of his conversation

with Tracy Boston defense counsel objected, and the objection was

sustained. The challenged question, i.e., the nature of the

conversation between Hembree and Brice (clearly a rehash of the

Boston interview) came almost immediately after the objection to

the prosecutor's question concerning the topic of Hembree's

discussion was sustained. The prosecutor's later question, which

was objected to by defendants, put before the jury in an indirect

manner the same irrelevant hearsay testimony which the district

court had prohibited the prosecutor from eliciting. To the

discredit of the prosecutors, this was not an isolated situation.

 A similar instance involved the testimony of Deputy 

Robert Davidson of the DeSoto Parish Sheriff's Office. Davidson
29

testified that he talked to Don Johnson of the Shreveport Police

Department. He was then asked "[w]hat did you do after talking to

Don Johnson with the Shreveport Police Department." (17 R. 1772).

Following defendants' objection to the question which was

overruled, Davidson answered that he "continued surveillance and

focused investigation on more than Renee Smith." Id. Davidson was

then asked "[w]ho did you focus the investigation on?" (17 R.

1772). Defendants objected to the question; however, the district

judge overruled the objection and instructed the jury that "this is

being offered not for the truth of the matter, that may have been

said to him, but rather to show simply a basis for action here at

this point." Id. There was, of course, a basis for this ruling,

just as the judge instructed the jury. 

 Nevertheless, Davidson's answer: "Darrell Adams and George

Robinson" demonstrated that the evidence should have been excluded.

(17 R. 1773). The identity of the "focus" of the investigation had

limited, if any, probative value. It was entirely unnecessary to

explain the basis for further activity by the witness. By any

account the probative value was insufficient to offset the

prejudice to Adams resulting from the direct implication that a

Shreveport policeman, not subject to cross-examination, had given

information, itself probably not admissible, which caused

defendants to become the "focus" of a narcotics investigation. See

United States v. Gomez, 529 F.2d 412, 416 (5th Cir. 1976).

 The prejudice to Adams was compounded when Davidson was

allowed to answer the prosecutor's inquiry as to "what else did you
30

focus your investigation on?". (17 R. 1774). Davidson replied

"ProCare Engine Exchange in Houston." Id. Because the jury had

before it evidence that Adams owned ProCare at the time of

Davidson's investigation, this response (surely anticipated by the

prosecutor) further implicated Adams.

 There are several additional examples which, although they do

not involve "opinion" evidence as to defendant's unlawful

activities directly, do so implicitly. In those instances, the

jury would reasonably infer that information obtained in an out of

court conversation between a testifying police officer and an

informant or other law enforcement officer implicated a defendant

in narcotics activity. For example, a prosecutor asked Mike

Kellum:

 [d]uring the course of your narcotics investigation

 have you become familiar with the names Eric Lowery

 and Larry Hill as focuses of any narcotics investigation

 in Shreveport? 

(17 R. 1727). Defendants objected to the question, and the

objection was sustained. The prosecutor then explained to the

district judge that she was attempting to ask Agent Kellum if he

had personal knowledge of that information. The judge told Kellum

that he could answer if he had "personal knowledge." Kellum

replied "[y]es, I do." Id. On motion of defendants the judge

ordered the answer stricken and instructed the jury to disregard

the answer. Nevertheless, the irrelevant question was highly

prejudicial to Hill and Lowery; the "personal knowledge" of

"information" regarding a defendant's narcotics activity is never

admissible. No prosecutor should ever ask such a question. The
 

10 The challenged comments were made by two different assistant

United States Attorneys.

31

judge's instruction to the witness regarding "personal knowledge"

obviously was not meant to refer to information from others;

however, that is what the answer reflected. This was not an

isolated instance of such questioning. 

 Michael Hembree testified that he checked certain records

relating to Lowery, Hill and other individuals. Despite the ruling

just described, Hembree was asked "[w]ere any of these names

already familiar to you as a result of your personal

investigation?" (20 R. 2690). Once again defendants' objection was

sustained, but the question carried its own damaging garbage. 

 Based upon the large number of instances of similar improper

questioning we conclude that the prosecutors intentionally used

such questioning as part of their trial strategy. Our conclusion is

strengthened by the fact that both prosecutors used the same

improper method of questioning. The questions were clearly

improper and highly prejudicial to the defendants. Prosecutors have

an obligation "to refrain from improper methods calculated to

produce a wrongful conviction. . .." United States v. Murrah, 888

F.2d 24, 28 (5th Cir. 1989). A breach of that obligation

constitutes serious prosecutorial misconduct, the effect of which

we discuss later.

E. Comments on Defendants' Failure to Testify

 Various appellants challenge five statements by prosecutors,10

contending that the statements were improper comments upon
32

defendants' failure to testify. We conclude that in two instances

prosecutors did violate appellants' Fifth Amendment rights.

 Prosecutors are prohibited from commenting directly or

indirectly on a defendant's failure to testify in a criminal case.

United States v. Montoya-Ortiz, 7 F.3d 1171, 1178 (5th Cir. 1993).

A prosecutor's remarks constitute impermissible comment on a

defendant's right not to testify, if the prosecutor's manifest

intent was to comment on the defendant's silence or if the

character of the remark was such that the jury would naturally and

necessarily construe it as a comment on the defendant's silence.

United States v. Collins, 972 F.2d 1385, 1406 (5th Cir. 1992),

cert. denied, 507 U.S. 1017, 113 S.Ct. 1812, 123 L.Ed.2d 444

(1993). A prosecutor's intent is not "manifest" if there is an

equally plausible explanation of the prosecutor's remark. United

States v. Collins, 972 F.2d at 1406. The challenged remarks must

be considered in the context of the case in which they are made.

United States v. Montoya-Ortiz, 7 F.3d at 1179. Some factual

background is necessary in order to consider the prosecutors'

comments in context. 

 During closing argument, a defense counsel placed a photograph

of a witness for the prosecution in the witness stand and discussed

the witness's testimony. During the rebuttal argument the

prosecutor removed the photograph from the witness stand, placed it

on an easel at the end of the jury box, and surrounded the

photograph with pictures of Alvarado, Adams, Felicia Lowery, and

Angela Tubbs. Thereafter he stated:
33

 But I submit from the testimony you've heard that was,

 that was, a man chosen by Darrell Adams, mind you, the

 first relationship. That was a man chosen by Darrell Adams

 to take care of and take charge of the most precious things

 in Darrell Adam's everyday life, drugs and money. That

 was the first choice made. That was the first relationship

 made.

 And to take this Houston Police Department glamour shot

 of fat addict Roy. Come on. Is that not to some extent

 misleading? Judging by his appearance. But to set that

 photograph in that stand without including the other 

 players--

 

(40 R. 8074). Defendants' objected, and the jury was excused. The

district judge ruled that the statement was not a comment on the

defendant's failure to testify, but he offered to instruct the jury

to disregard the remark. Defendants declined the offer. The

prosecutor then continued his rebuttal argument stating:

 You cannot be permitted to conclude from this Houston

 Police Department glamour shot of Roy Patterson --

 You cannot, you cannot, be permitted to conclude that

 he acted alone, that he was not involved in some 

 combination, some confederation, some conspiracy,

 to possess with intent to distribute cocaine and the

 reasonably foreseeable consequence of cocaine, crack

 cocaine, and marijuana. You cannot.

(40 R. 8082-83).

 The prosecutor was attempting to persuade the jury that the

witness was not acting alone, that he was acting as part of a

conspiracy. The prosecutor's argument, although unartful, does not

demonstrate manifest intent to comment on the defendants' silence,

nor would a jury necessarily construe it as a comment on their

failure to testify. The statement was not an improper comment on

defendants' failure to testify.

 The second comment made during the rebuttal argument is the

following: 
34

 [Counsel for Lowery] also submitted to you that his

 client has led an open life. If it's so open, why don't

 you put your automobiles in your name? If it is so open,

 why don't you tell us what you do to make in this cash 

 business that you moved to after you've worked at

 Cantonese Grocery. . ..

(40 R. 8099). Lowery moved for a mistrial. The motion was denied

based on the prosecutor's explanation, outside the presence of the

jury, that his comment was directed to Lowery's failure to file

income tax returns. The judge then instructed the jury to disregard

the statement. 

 No manifest intent to comment on the defendant's failure to

testify is demonstrated in the cited statement. The prosecutor's

explanation, i.e., that he was commenting on the lack of income tax

returns, is a plausible explanation for the statement. Moreover,

the jury would not necessarily and naturally view the statement as

a comment on Lowery's failure to testify. The statement did not

violate appellants' Fifth Amendment rights.

 Appellants also attack a question posed by the prosecutor to

IRS Special Agent Jackson. Agent Jackson was asked: "[a]t any time

did A.D. Ernest invoke his right to remain silent?" The agent

stated "[h]e did later." (31 R. 6044). At this point in the trial

Ernest was a defendant; later he entered a guilty plea.

 The inquiry was restricted to Ernest and did not implicate any

appellant. The jury would not necessarily construe a statement

that one defendant invoked his right to remain silent as a comment

on the remaining defendants' failure to testify. Moreover,

defendants' failure to contemporaneously object to the question

deprived the court of the opportunity to give a curative
35

instruction to eliminate or lessen any prejudice to appellants.

The question does not constitute error as to any appellant.

 One troublesome comment occurred during the redirect

examination of Roosevelt Gatterson. Again, background is essential

to place the comment in the proper context. During direct

examination Gatterson testified about a number of activities in

which he engaged in furtherance of the conspiracy. During crossexamination he was asked three times if anyone could corroborate

his testimony concerning three such activities, e.g., cocaine

deliveries. Gatterson responded "no" to each of the three

questions. On redirect the prosecutor inquired "[a]ren't there

some people in this courtroom that can back up what you say?" (15

R. 1165). Simultaneously the prosecutor made a sweeping arm

gesture indicating the individuals seated at counsel tables. The

judge immediately told the jurors to disregard the impermissible

question and instructed them as follows:

 no defendant is required to present any evidence

 in this case nor to testify in this case. You may 

 not, if any one of them choose not to do so, consider 

 that against them or in your consideration of the 

 evidence at all or in any respect whatsoever.

 You've been instructed on that before. You're

 instructed again. Mr. Dies has asked an improper

 question in turning as he did toward the defendants

 in this respect. They are under no burden to make

 a response on any of that. Therefore, you're 

 instructed to disregard entirely that question.

(15 R. 1166).

 The prosecutor demonstrated manifest intent to comment on the

defendants' failure to testify. In responding to the crossexamination to the effect that there were no witnesses who could
36

corroborate Gatterson's testimony, the prosecutor implied that

there were such people in the courtroom, obviously referring to the

defendants. No one else in the court room could have witnessed the

events; only the defendants could reasonably be thought to be

capable of providing corroboration. The question was bad enough,

but the prosecutor made it worse by use of the arm gesture

emphasizing that he was referring to the defendants' failure to

testify. The prosecutor's question and gesture clearly constituted

an impermissible comment on the defendants' silence, serious

prosecutorial misconduct.

 There is more: during the first portion of the government's

closing argument, in highlighting some of the court's instructions

on the law that the jury was likely to hear following closing

arguments, a prosecutor stated:

 This also says that in an impeachment of prior

 inconsistencies instruction something that I want to

 remind you of and the instruction actually reminds

 you of. It reminds you that a defendant has the 

 right not to testify. That is constitutional right.

 It is yours. It is mine. It is theirs. Please

 value it. I do. Don't take into consideration the

 fact that whether or not anyone testified in this case

 is inappropriate.

 But what you also can't do in a situation like this is

 go back into that jury room and make up a story for them.

 That is impermissible by law. You can't play "what if."

 You can't say, "Well, if they testified, well, maybe they

 would have explained this. Maybe they would have said 

 that." That's not allowed and that's fair.

(39 R. 7779-80). Defendants objected to the argument as an

impermissible comment on their failure to testify and requested a

mistrial. The judge overruled the objection stating "[t]he jury is

going to follow the instructions of the court on that." Id.
37

 The government urges that there was no manifest intent to

comment on the failure to testify, because it is equally plausible

that the comment was a plea for the jury to base its verdict solely

on the evidence and not on speculation and conjecture, and that the

jury would not necessarily have considered the remark as a comment

on the defendants' failure to testify. Mindful that wide latitude

is accorded counsel during closing argument, we nevertheless deem

the prosecutor's statement to be error. The fact that the

prosecutor was not attempting to have the jury infer guilt due to

the defendant's failure to testify does not render the statement

permissible. The statement was a direct comment on the failure to

testify. Even though the prosecutor cautioned the jury not to

consider whether the defendants testified at trial, his comment

focused the jury's attention on the fact that the defendants did

not testify. It matters not that the prosecutor was paraphrasing

the court's instruction. A statement by the court referring to the

defendant's right not to testify is far different from a similar

reference by the prosecutor in closing argument; indeed, a

defendant who has chosen not to testify probably has the right to

request the court to delete such a reference from the court's

charge. In any event, the last portion of the prosecutor's

statement had no basis in the court's charge and was arguably an

incorrect statement of the law. Nothing precludes jurors from

theorizing in their own minds as to a defendant's version of the

facts in the absence of testimony from the defendant. Our system

of justice rigorously guards the right of an accused to remain
38

silent and not to testify. Prosecutors are obligated never to

attempt to sway a jury in any way because of the exercise of an

accused of that right. To suggest that a defendant's decision not

to testify somehow limits jurors' mental processes, e.g., with

respect to inferences to be drawn from direct evidence, violates

that obligation. The prosecutor's statement constitutes error.

 EFFECT OF PROSECUTORIAL MISCONDUCT

 Having concluded that the prosecutor's references to the

defendants' failure to testify and their improper questioning of

various law enforcement officials constitute serious misconduct, we

must now determine whether those tactics cast serious doubt upon

the correctness of the jury's verdict. Otherwise, the errors are

harmless and do not justify reversal. United States v. Palmer, 37

F.3d 1080, 1085 (5th Cir. 1994), cert. denied, U.S. , 115

S.Ct. 1804, 132 L.Ed.2d 265 (1995).

 In examining the effect of the prosecutors' impermissible

comments, we consider three factors: "the magnitude of the

prejudicial effect of the remark, the efficacy of any cautionary

instruction, and the strength of the evidence of the defendant's

guilt." United States v. Bermea, 30 F.3d 1539, 1563 (5th Cir.

1994), cert. denied sub. nom., 513 U.S. 1156, 115 S.Ct. 1113

(1995).

 The prejudicial effect of the comment and gesture during

Gatterson's testimony was slight. The question was asked during

the second week of a trial that lasted twenty-nine (29) days

extending over a period of approximately eight weeks. The prejudice
39

was also lessened because the question was asked during the

government's case-in-chief. At that time the jury did not know

that the defendants would not testify and would therefore be less

inclined to construe the question as a comment on the defendants'

silence. The judge's timely and thorough jury instruction further

mitigated the effect of that improper comment.

 The prosecutor's comment during closing argument was more

prejudicial. It was a direct comment on defendants' failure to

testify, and it occurred only one day before the jury began

deliberations. 

 The prejudice was mitigated somewhat by the trial judge's

instruction prior to the commencement of jury deliberations that:

 The law does not require a defendant to prove

 his innocence or to produce any evidence at

 all and no inference whatever may be drawn 

 from the election of a defendant not to testify.

 Yesterday morning when [the prosecutor] was

 giving -- going over some of the instructions,

 she expected that I would give and remarked on

 one of these passages and [defense counsel]

 moved for a mistrial and I denied that and

 said the jury would follow my instructions. 

 My instructions are these.

 Again, no inference whatever may be drawn from

 the election of a defendant not to testify.

 

(40 R. 8174). While the harm was mitigated by this jury

instruction, the prejudice remained. The constitutional right of a

defendant to choose not to testify is a fundamental tenet of our

system of justice. The prejudice resulting from a direct reference

by a prosecutor to the exercise of that right, coupled with an

attempt to use the failure to testify to limit the jurors personal
40

deliberative process cannot be completely cured by a court

instruction. The remaining prejudice, especially if cumulated with

prejudice resulting from other misconduct, may be sufficient,

absent substantial evidence of a defendant's guilt, to cast doubt

upon the correctness of the jury's verdict.

 As previously stated, the prosecutors' improper questioning of

law enforcement officials was highly prejudicial to those

appellants directly implicated. There are no factors mitigating

that prejudice. 

 To complete the analysis as to whether the prosecutors' errors

justify reversal of convictions, we must measure the prejudice

resulting from the misconduct against the strength of the evidence

as to each appellant's guilt. 

A. Darrell Adams

 There is no need to repeat the extensive evidence already

recounted in detail. Suffice it to say that the evidence against

Adams is overwhelming. Bosia Cash, Roosevelt Gatterson, Officer

Henry King, Kimela Lomax, Stevenson McClendon, Bruce Embrey, and

Roy Patterson all identified Adams as the supplier of narcotics

being transported to Shreveport for distribution over a lengthy

period. There was a great deal of evidence that Adams directed the

activities of his co-conspirators in Houston, arranged for the

narcotics to be transported to Shreveport, identified the person to

whom the drugs were to be delivered, and collected and counted the

vast profits derived from these illegal activities. 

 There is also considerable circumstantial evidence against
41

Adams. Documents seized from Adams' office at ProCare were

identified by FBI Agent Harold Clouse as drug ledgers.

Additionally, Adams engaged in various practices common among those

involved in narcotics trafficking, including listing pager and

telephone service in the name of another. Over a two year period,

thirty three (33) different pagers were billed to ProCare.

 There is also strong financial evidence of Adams' guilt.

Receipts for wire transfers of money were retrieved from his

garbage, two for transfers of $4,000 and one for $3,000. Adams

frequently had large amounts of cash in his possession; he made

cash payments of $5,000 and $5,341.82 on a Lexus automobile and

kept $10,000 in cash in a shoe box in his closet. The search of

Adams' house at the time of his arrest yielded $32,000: $3,000 in

a bag in a closet in the master bedroom, $13,000 in a shed, and

$19,000 in a bag behind the washing machine. 

 The financial condition of ProCare also provides evidence of

Adams' guilt. Based on records from the State Comptroller's

Office, in 1993 ProCare's reported sales were approximately the

same as those established by the records of sales seized at

ProCare. However, bank deposits for the business in 1993 were

significantly higher. That surplus is not accounted for by

transfers of money from Adams' personal back account to the

corporation's account. After deducting Adams' expenditures from

his personal bank account, insufficient funds remained to account

for the funds deposited into ProCare's account. Although Adams

purchased Procare in 1991, his income tax return for that year does
42

not record any income from ProCare. Adams did not file income tax

returns in 1992 and 1993. On a credit application for the purchase

of a car executed in October 1993, Adams stated that his yearly

salary from ProCare was $75,000. 

 Considering the overwhelming evidence against him, the

prosecutorial misconduct does not rise to the level of reversible

error as to Adams.

B. Gonzalo Alvarado

 As with Adams, the evidence against Alvarado is overwhelming.

Several witnesses named Alvarado as Adams' source of drugs.

Stevenson McClendon testified that he purchased cocaine from

Alvarado on behalf of Adams. Gatterson testified that he picked up

cocaine destined for Shreveport from Alvarado. Roy Patterson

testified that Alvarado personally delivered five kilograms of

cocaine to him at the stable used by Adams. 

 Witnesses saw Adams deliver money to Alvarado, and there was

evidence of frequent communication between Adams and Alvarado,

including testimony that Alvarado called ProCare daily. When Bosia

Cash was arrested and the cocaine he was transporting was seized,

Adams sent Gatterson to inform Alvarado of the loss. 

 During the search of Alvarado's house twelve (12) pounds of

marijuana and a five pound scale were seized. A document seized

from Adams' office at ProCare, identified as a drug ledger,

indicated a payment to Alvarado for cocaine. 

 Alvarado challenges his convictions based solely on the two

comments by prosecutors on the defendants' failure to testify.
43

Considering the overwhelming evidence of Alvarado's guilt we find

that the prosecutors' improper comments do not constitute

reversible error, and we affirm his convictions.

C. Eric Lowery

 Considering the strength of the evidence against Lowery we

conclude that the prosecutors' misconduct did not have an effect on

the outcome of his trial. Thus, the misconduct was harmless error

as to Lowery. 

 Roy Patterson testified that in approximately May 1993,

Lowery and Johnston came to ProCare and Lowery arranged with

Patterson to deliver a shipment of marijuana to Shreveport.

Roosevelt Gatterson testified that he saw Lowery at ProCare on two

occasions; both times Lowery met with Adams. On the second occasion

Lowery was accompanied by Johnston. Gatterson testified that he

was told that Lowery and Johnston were at Procare for some type of

narcotics deal. 

 Roy Patterson also testified that large amounts of cocaine and

marijuana were delivered directly to Lowery. Patterson testified

that Lowery participated in the weighing of one marijuana delivery

to Shreveport, and Derrick Patterson corroborated Lowery's

involvement in that delivery of marijuana. 

 Roy Patterson testified that he received large amounts of cash

from Lowery and delivered that money to Adams. Kimela Lomax

testified that Johnston delivered a large amount of cash to Adams'

house. Lomax further testified that when Adams confronted Johnston

with an accusation that the money Johnston delivered was "short,"
44

Johnston called Lowery, who discussed the situation with Adams. 

 There is also strong circumstantial evidence of Lowery's

guilt. Lowery phoned and visited Adams at ProCare, and Lowery and

Adams met in Shreveport a number of times so that Adams could "take

care of business." Murray Franks, a salesman with EconoPage,

testified that he sold several pagers to Lowery during the period

covered by the conspiracy.

 During the period covered by the conspiracy Lowery purchased

a Grand Prix automobile; he told the car salesman that he did not

want to pay more than $10,000 cash for the car. Lowery paid for

the Grand Prix in cash, primarily in denominations of $50 or less.

He registered the vehicle in Jennifer Gerard's name. The vehicle

Lowery traded in at the time he purchased the Grand Prix was also

registered in Jennifer Gerard's name. 

 In December 1993, Lowery's brother Walter Gerard used $5,000

cash received from Lowery to pay part of the purchase price of an

automobile. Although the vehicle was registered in Walter Gerard's

name and Gerard had a set of keys, it was clear that the car was

Lowery's. Lowery failed to file income tax returns for the years

1991-1993.

D. EDWARD JOHNSTON

 There is abundant evidence of Johnston's guilt. Kimela Lomax

testified that she witnessed an exchange of drugs and money between

Johnston and Adams. Gatterson testified that Johnston accompanied

Lowery to ProCare. Roy Patterson testified that Johnston appeared

at ProCare with Lowery on one occasion and that after Lowery made
45

arrangements for Roy Patterson to transport thirty (30) pounds of

marijuana to Shreveport, Johnston transferred a bag into

Patterson's truck. Roy Patterson also testified that Johnston

transported marijuana and cocaine for Adams. Johnston accepted

delivery of four kilograms of cocaine from Roy Patterson for

delivery to Shreveport. 

 Kimela Lomax testified that Johnston delivered large amounts

of cash to Adams on more than one occasion. On one of the

occasions Adams informed Johnston that the money was "short;" in

response Johnston telephoned Lowery. 

 Johnston was employed at the City Lights Club owned by Hill.

On one occasion Johnston was stopped for a traffic offense shortly

after leaving City Lights. He identified the vehicle as belonging

to Hill, even though it was registered to Marilyn Timmons. A

search of the vehicle revealed $1,802 and two guns which Johnston

said belonged to Hill. 

 Because Johnston was not directly implicated by any of the

prosecutor's improper questioning of law enforcement officials,

that misconduct was not damaging to him. The prosecutors' comments

on the defendants' failure to testify are the sole errors affecting

Johnston. Because the evidence of Johnston's guilt is strong, the

improper comments are not reversible error. 

HILL

 Hill joins in the complaints about prosecutorial misconduct;

alone among the defendants he claims that in any event the evidence

is insufficient to support his conviction. We conclude that had
46

prosecutorial misconduct not occurred, we would affirm Hill's

conviction. But the evidence against Hill is not strong enough to

support a conclusion that the prejudice resulting from the

prosecutors' misconduct did not substantially affect his right to

a fair trial.

 The essential elements of a conspiracy under 21 U.S.C. §846

are: (1) an agreement between two or more persons to violate the

narcotics laws; (2) a defendant's knowledge of the agreement; and

(3) his voluntary participation in that agreement. United States

v. Morris, 46 F.3d 410 (5th Cir. 1995). Hill concedes that the

government established an agreement to violate the drug laws, but

contends that the government failed to prove that he was part of

the agreement.

 In reviewing a claim that there is insufficient evidence to

support a conviction, we must determine whether "viewing the

evidence and the inferences that may be drawn from it in the light

most favorable to the verdict, a rational jury could have found the

essential elements of the offense beyond a doubt." United States

v. Morgan, 117 F.3d 849, 853 (5th Cir. 1997). We are required to

"accept all credibility choices that tend to support the jury's

verdict." Id., quoting United States v. Anderson, 933 F.2d 1261

(5th Cir. 1991).

 Applying these tests, we conclude that there is sufficient

evidence against Hill to sustain his conviction had serious

prosecutorial misconduct not occurred. There is direct evidence of

Hill's participation in the conspiracy. Roy Patterson and Derrick
47

Patterson testified that Hill participated in one delivery of

thirty (30) pounds of marijuana. The Pattersons testified that

Hill led the Pattersons and Lowery to Jennifer Gerard's house,

unlocked the door to the house and helped weigh the marijuana.

 There is also circumstantial evidence of Hill's guilt. Hill

owned the City Lights Club which Lowery managed. Hill referred to

Lowery as his partner. As already discussed, the evidence as to

Lowery's participation in the conspiracy is overwhelming.

Appellant Johnston, Jennifer Gerard, and Walter Gerard all worked

at City Lights at times during the period of the conspiracy.

Jennifer and Walter Gerard were paid in cash. 

 On December 10, 1993, Johnston was stopped a short distance

from the City Lights Club driving a truck registered to Marilyn

Timmons but identified by Johnston as belonging to Hill. A large

sum of cash ($1,802) was found in the truck; Johnston stated that

the money belonged to Hill. The search of the vehicle uncovered a

picture of Hill, Lowery, Adams, Derrick Patterson, and two other

men, taken at City Lights. On the same night that the photograph

was taken, Derrick Patterson rode with Lowery and Adams to the City

Lights Club. Patterson heard Adams ask Lowery about the quality of

the marijuana. Lowery told Adams that he would have to ask Hill

because Lowery "didn't mess with it." (27 R. 4753).

 Ronnie Holden, a friend of Hill, acquired a pager for

Hill, and submitted the bills for the pager to him for payment.

Dexter Edwards, an account executive for Cellular One testified

that Hill purchased a cellular telephone from Cellular One and that
48

cellular phone service established in the names of Marilyn Timmons

and Debra Hall was used by Hill. Records of that cellular service

indicate that calls were made to ProCare in June and September of

1993.

 When Hill was arrested, he asked an unidentified individual to

contact "Eric" and "[g]et me some lawyers." (20 r. 2776-78). Two

voided ProCare checks named "Larry Hill" as the payee. Hill did

not file an income tax return for 1992 or 1993. Although Hill

owned City Lights for a portion of 1991, his income tax return for

that year does not indicate any income from the club.

 Although the evidence of Hill's participation in the

conspiracy is limited, "a rational jury could have found that the

evidence establishes guilt beyond a reasonable doubt." United

States v. Salazar, 958 F.2d 1285, 1290-1291 (5th Cir.), cert.

denied, 506 U.S. 863, 113 S.Ct. 185, 121 L.Ed.2d 129 (1992).

 The evidence against Hill is far less compelling than that

against the other defendants, in part because it is largely

circumstantial. The testimony of the Pattersons is the only

evidence that directly links Hill to illegal narcotics trafficking,

and that testimony involved only one instance out of many months of

narcotics activity by other defendants. The only other evidence

against Hill is weak circumstantial evidence. Thus, the prejudice

resulting from the prosecutors' improper questioning and the

improper comments is more likely to have denied him his right to a

fair trial. 

 The jury heard a law enforcement officer testify that as a
 

11 Because we reverse Hill's conviction we do not address his

contention that his sentence was improperly calculated.

49

result of information supplied by others he identified Hill as the

focus of the investigation. Such testimony coming from a source

generally viewed as highly credible is extremely prejudicial. The

jury also heard two improper references to the fact that Hill did

not testify at his trial. Weighing the evidence of Hill's guilt

against the extreme prejudice he suffered due to the prosecutors'

misconduct, we conclude that the cumulative effect of the errors

substantially affected Hill's right to a fair trial. Accordingly,

we reverse his conviction and remand for a new trial.11 We are very

reluctant to set aside a jury verdict rendered after a long,

expensive, contentious trial, at which the district judge performed

a creditable job of managing overzealous counsel. Nevertheless,

somewhere we must draw the line and send a message to prosecutors

that the Constitution governs their actions at trial. This is such

a case.

 SENTENCING ISSUES

 Edward Johnston and Eric Lowery appeal their sentences. They

each assert that their base offense level was improperly

calculated. Johnston also contends that his criminal history

category was not properly computed, and that the district judge

erred in stating during the sentencing that he did not have the

authority to depart from the Sentencing Guidelines. 

Conversion of $90,000 to Cocaine Quantity

 We apply the clearly erroneous standard of review to the
50

district court's factual determination regarding the quantity of

drugs used to establish the base offense level. United States v.

Morris, 46 F.3d 410, 419 (5th Cir.), cert. denied, 

U.S. 115 S.Ct. 2595 (1995). A factual finding is not clearly

erroneous if it is plausible in light of the record as a whole.

Id. A preponderance of the evidence must support the district

court's determination. United States v. Ruiz, 43 F.3d 985, 989

(5th Cir. 1995).

 The base offense level under the Sentencing Guidelines is

determined in part by the amount of drugs involved. Both Johnston

and Lowery claim that the district court erred in converting

$90,000 in cash delivered by Johnston to Adams into five kilograms

of cocaine for the purpose of determining their base offense

levels. They contend that there is no evidence that the cash

represented proceeds of cocaine transactions.

 Kimela Lomax testified that when Johnston delivered the money,

Adams complained that the money was short. There is evidence that

when Johnston called Lowery to discuss the shortage, Adams spoke to

Lowery and told him that he would be "minus one." Lomax testified

that "minus one" meant one "kilo." It is reasonable to infer that

"minus one" was a reference to a kilogram of cocaine.

Additionally, there is evidence that $18,000 is a reasonable price

for a kilogram of cocaine. 

 Although there is evidence that Lowery and Johnston were

involved in trafficking marijuana as well as cocaine, there is no

evidence of a single marijuana shipment large enough to account for
51

proceeds of $90,000. However, there is considerable evidence of

cocaine shipments equalling or exceeding five kilograms. The

district judge's conversion of the $90,000 into five kilograms of

cocaine was not erroneous.

 Johnston also contends that his criminal history category was

improperly computed. Johnston was assessed three criminal history

points: one for driving under suspension and two because the

conviction involved in this appeal occurred while Johnston was on

probation for driving under suspension. Because Johnston had more

than one criminal history point he did not qualify for the "safety

valve" provision in §5C1.2 of the Sentencing Guidelines. 

 Johnston urges two grounds in support of his contention that

the district court committed error in calculating his criminal

history category: the driving under suspension charge was not

timely disclosed, thereby rendering it impossible for his attorney

to investigate the charge, and the government failed to prove the

driving under suspension offense by a preponderance of the

evidence. 

 Although the driving under suspension charge appeared in the

Presentence Investigation Report, detailed information concerning

the charge and a copy of the documents supporting that charge were

not provided to defense counsel until the addendum to the report

was filed on the morning of sentencing. Nevertheless, the claim

that the untimely disclosure prohibited counsel from investigating

the charge is without merit. Johnston's counsel was given time at

the sentencing hearing to review the addendum. Thereafter he
52

indicated that he was ready to proceed with the sentencing. Had

counsel desired or required additional time to investigate the

validity of the driving under suspension charge, he should have

advised the court of that need. Considering counsel's statement

that he was ready to proceed with the sentencing, defendant cannot

now claim that he had insufficient time to investigate the charge.

 Johnston's contention that the government failed to establish

the driving under suspension offense by a preponderance of the

evidence is also without merit. The district judge examined the

record of the offense and determined that there was a valid

conviction. There is no evidence to the contrary.

 Johnston also contends that his sentence should be vacated

because the district judge mistakenly believed that he did not have

the authority to depart below the guidelines range. In support of

his contention, defendant relies on the following comments by the

district judge:

 the United States laws control this matter, including

 the guidelines that are prescribed by the United States

 Sentencing Commission, and a court is required by law

 to sentence within the guideline range. The defendant,

 having been convicted by the findings of a jury, leads

 then to the requirement that the judge impose a sentence

 as prescribed by law. It's not within the power of the

 judge to impose or not to sentence or to let one off or

 to let one proceed without having a sentence within the

 guideline range prescribed by federal law.

(46 R. 32) The comments were made in response to Johnston's

mother's request that her son be allowed to go home with her. The

comments are a reasonable explanation of why her request could not

be granted. The experienced district judge surely was aware of his

power to depart downward from guidelines; indeed he did so in
 

12 The district judge concluded that a criminal history

category of II overrepresented the seriousness of Johnston's

criminal history.

53

assigning Johnston a criminal history category of I.12

ADAMS' 18 U.S.C. §924(c) CONVICTION

 Adams was convicted on count 15 of the superseding indictment,

which charged that he "did knowingly and unlawfully aid, abet, and

assist others, known and unknown to the Grand Jury, to use and

carry a firearm during and in relation to a drug trafficking crime"

in violation of 18 U.S.C. §924(c)(1)." Based on Bailey v. United

States, U.S. , 116 S.Ct. 501, 508 (1995), Adams contends

that his conviction on that count must be reversed.

 Adams admits that there is evidence that he aided and abetted

Roosevelt Gatterson in "carrying" a weapon in violation of 18

U.S.C. §924(c). However, Adams contends that because the jury was

improperly instructed as to the meaning of "use" as construed in

Bailey, there is no way to determine whether the conviction was

based on "use" or "carry", and therefore his conviction must be

reversed. The government concedes that there is insufficient

evidence of "use" as construed in Bailey to uphold Adams'

conviction and that the conviction must be reversed and the case

remanded for a trial on the "carrying" theory only. See United

States v. Fike, 82 F.3d 1315, 1328 (5th Cir.) cert. denied sub.

nom, U.S. , 117 S.Ct. 241 (1996). 

CONCLUSION

 For the reasons stated, we affirm the conviction of Gonzalo

Alvarado and the convictions and sentences of Edward Johnston and
54

Eric Lowery. We also affirm the convictions of Darrell Adams

except as to his conviction on count 15, which is reversed and

remanded for trial on the charge of "carrying" a firearm in

relation to a drug trafficking crime. We reverse the conviction of

Larry Hill on count 1 and remand for a new trial.

ENDRECORD 
55

KING, Circuit Judge, concurring in part and dissenting in part:

I respectfully dissent from the judgment of the panel

reversing the conviction of Larry Hill on Count 1 of the

indictment. Judge Duplantier’s opinion does a careful job of

outlining the substantial evidence against Hill. In my view, the

prosecutorial misconduct that occurred here does not cast serious

doubt on the correctness of the jury’s verdict. I would affirm his

conviction. In all other respects, I concur in the panel’s

judgment and in Judge Duplantier’s superb opinion.