              IN THE UNITED STATES COURT OF APPEALS
                      FOR THE FIFTH CIRCUIT

                         _____________________

                              No. 98-50936
                         _____________________


UNITED STATES OF AMERICA,

                                 Plaintiff-Appellee,

     v.

GUSTAVO LOPEZ-BENITEZ,

                              Defendant-Appellant.
_________________________________________________________________

           Appeal from the United States District Court
                 for the Western District of Texas
                          (DR-98-CR-101-1)
_________________________________________________________________

                           October 15, 1999

Before KING, Chief Judge, and GARWOOD and STEWART, Circuit
Judges,

KING, Chief Judge:*

     Defendant-Appellant Gustavo Lopez-Benitez (Lopez) appeals

his conviction for possession with intent to distribute marijuana

in violation of 21 U.S.C. § 841(a)(1), arguing that the district

court erred in (1) denying his motion to suppress, concluding

instead that Border Patrol officers had reasonable suspicion to

stop the vehicle he was driving; (2) denying his motion for

mistrial despite prosecutor questioning regarding Lopez’s post-

arrest silence; and (3) denying his request for jury instructions

     *
        Pursuant to 5TH CIR. R. 47.5, the court has determined
that this opinion should not be published and is not precedent
except under the limited circumstances set forth in 5TH CIR. R.
47.5.4.
regarding the knowledge element of his charged crime. We find

that the Border Patrol officers had reasonable suspicion to stop

the vehicle Lopez was driving, but we reverse and remand for a

new trial because we also conclude that prosecutorial misconduct

prejudiced Lopez’s rights to a fair trial. As a result, we do not

address the jury instruction issue.



                               I.

                   FACTS & PROCEDURAL HISTORY

     Around 11:30 p.m. on February 23, 1998, Border Patrol

officers Troy Meredith and Ignacio Guerra, in a marked Border

Patrol Bronco, were traveling west on Highway 277 between Carrizo

Springs and Eagle Pass. They were approximately 15 miles from the

U.S. border when they saw two eastbound sedans traveling one to

two car lengths apart from one another. Officer Meredith

testified that Highway 277 was a route commonly used by

smugglers, and that he had encountered drug- and alien-smuggling

activity on Highway 277 during his three years of experience

monitoring the road. He affirmed that the area in which the two

sedans were spotted was ranch land, and that sedans were not

ranch traffic. He also testified that shift changes occurred

between 11:00 and midnight, and that the checkpoint on Highway

277 had closed at 8:00 p.m. At the time he and Officer Guerra

spotted the two vehicles, the checkpoint on Highway 57, another

road leading away from the border, was open.




                                2
     The officers turned around and followed the rear vehicle, a

Chevrolet Cavalier. A license-plate check of that vehicle showed

it was registered in Austin, Texas. The officers then passed the

Cavalier and pulled in between the two cars. Officer Meredith

testified that their pulling in between the two cars caused the

rear vehicle to slow down and drop back by as much as half a

mile. A license-plate check of the car in front of them, a Ford

Escort, revealed it was also registered in Austin. Highway 57,

not Highway 277, is the most direct route to Austin.

     The officers stopped the Escort to check the immigration

status of the vehicle’s occupants. After determining the two

occupants were in the U.S. legally, the officers left to catch up

to the Cavalier, which had since passed them, to conduct an

immigration check. The driver of the Cavalier was Lopez, who, in

response to Officer Meredith’s query regarding his immigration

status, said he was in the country illegally. The officers

immediately put Lopez under arrest, escorted him to their patrol

vehicle, secured him in the back seat, and read him his rights.

     While Lopez was exiting the Cavalier, the officers detected

a smell, which they identified as the smell of marijuana, coming

from the vehicle. Although Lopez orally consented to a search of

the car, the officers nonetheless called for a K-9 unit in order

to have a dog inspect the vehicle. The dog alerted to the trunk

of the car. The trunk was opened with a key, and the officers

found sugar sacks painted black containing 51.8 kilos of

marijuana.


                                3
     A suppression hearing was held on July 6, 1998. The court

cited a number of factors as supporting the reasonableness of the

officers’ suspicions that the vehicles’ occupants were engaged in

criminal activity, including officer experience, the proximity to

the border, the nature of the road on which the stop was made,

the hour, that the vehicles were spotted between shift changes,

that both vehicles were registered in Austin and appeared to be

traveling in tandem, and that the vehicles were traveling on a

road on which the checkpoint was closed, rather than on the road

that was the more direct route to Austin but on which the

checkpoint was open. As a result, trial judge denied Lopez’s

motion to suppress the marijuana.

     The trial followed. During the prosecutor’s cross-

examination of Lopez, questions were posed regarding whether

Lopez had been read his rights upon arrest, whether he had asked

for a lawyer, and whether he had had occasion to tell his story

to the Border Patrol officers. Objection to each of these

questions was sustained. Lopez’s counsel moved for mistrial on

the ground that the prosecutor had violated Lopez’s

constitutional rights to counsel and to remain silent. This

motion was denied.

     The jury found Lopez guilty. A motion for a new trial was

denied. Lopez was sentenced to 37 months’ imprisonment, three

years’ supervised release, and a special assessment of $100. He

timely appeals.




                                4
                              II.

                        THE VEHICLE STOP

     In reviewing a denial of a motion to suppress, we accept the

district court’s findings of fact unless clearly erroneous, and

review its conclusion as to the constitutionality of the law

enforcement action de novo. See Ornelas v. United States, 517

U.S. 690, 699 (1996); United States v. Chavez-Villareal, 3 F.3d

124, 126 (5th Cir. 1993). The evidence presented at the pre-trial

suppression hearing must be viewed in the light most favorable to

the prevailing party, here the government. See United States v.

Villalobos, 161 F.3d 285, 288 (5th Cir. 1998).

     Lopez maintains that the district court erred in concluding

reasonable suspicion existed to justify pulling over the vehicle

he was driving, and therefore it erred in denying his motion to

suppress the marijuana discovered in the trunk. He first points

to the absence of evidence allowing officers to be reasonably

certain that the vehicle had recently crossed the border, arguing

that under United States v. Melendez-Gonzalez, 727 F.2d 407, 411

(5th Cir. 1984), the lack of such evidence required the court to

assess the remaining factors with care. He argues that those

other factors are insufficient to justify a stop.

     Under United States v. Brignoni-Ponce, 422 U.S. 873 (1975),

an officer on roving border patrol may stop and briefly

investigate a vehicle and its occupants if the officer is “aware

of specific articulable facts, together with [the] rational

inferences from those facts, that reasonably warrant suspicion


                                5
that the vehicles contain aliens who may be illegally in the

country.” 422 U.S. at 884. Each case turns on the totality of the

circumstances. See id. at 885 n.10; United States v. Cortez, 449

U.S. 411, 421-22 (1981). Based on an assessment of those

circumstances, “the detaining officers must have a particularized

and objective basis for suspecting the particular person stopped

of criminal activity.” Id. at 417-18. Factors that may be taken

into account include: (1) the characteristics of the area in

which the officers encounter the vehicle; (2) the detaining

officers’ previous experience with criminal activity; (3) the

area’s proximity to the border; (4) the usual traffic patterns on

the road in question; (5) information about recent illegal

trafficking in aliens or narcotics in the area; (6) the

appearance of the stopped vehicle; (7) the behavior of the

vehicle’s driver; and (8) the number, appearance, and behavior of

the passengers. See Brignoni-Ponce, 422 U.S. at 884-85; United

States v. Nichols, 142 F.3d 857, 865 (5th Cir.), cert. denied,

119 S. Ct. 621 (1998) (quoting United States v. Inocenio, 40 F.3d

716, 722 (5th Cir. 1994)).

     Overall, the circumstances in this case suggest that the

district court concluded correctly that officers’ suspicions were

reasonable. Lopez’s sedan was spotted in close proximity to

another sedan approximately fifteen miles from the border – not a

“substantial distance,” Inocencio, 40 F.3d at 722 n.7, by any

measure – in an area that was primarily ranch land. Cf.

Villalobos, 161 F.3d at 290 (spotting two cars in close proximity


                                6
on a sparsely traveled road does not itself justify a stop, but

may raise suspicions). The sedans were spotted on one of the two

main roads leading away from the border. That road was a known

smuggling route. Cf. id., 161 F.3d at 289 (“[T]he possibility

that Villalobos could have been an innocent traveler from

Presidio or Shafter does not negate the fact that the area

through which he was driving was both very close to the border

and very heavily traversed by border traffic.”); Nichols, 142

F.3d at 870 (stating that road’s reputation as smuggling route

adds to reasonableness of suspicion). The two sedans were spotted

at 11:30 p.m. when there was little to no other traffic on the

road. Cf. United States v. Lujan-Miranda, 535 F.2d 327, 329 (5th

Cir. 1976) (traveling at an unusual time of day may not itself

justify a stop, but is a permissible consideration). Lopez’s

reaction to the officers’ pulling in between the two sedans could

legitimately raise suspicions. Cf. Villalobos, 161 F.3d at 291

(“[N]oticeable deceleration in the presence of a patrol car can

contribute to reasonable suspicion . . . . Such deceleration may

be additionally suspicious when the car was not speeding to begin

with . . . .”). When these observations were combined with the

fact that two vehicles registered in Austin were traveling one to

two car lengths apart on a road that did not lead directly to

that city at a time when the checkpoint was closed on the road

taken but open on the more direct route,1 Officer Meredith, in

     1
        In Lopez-Valdez, 178 F.3d at 287, this Court found that
presence on FM2644 at 8:30 a.m. was insufficient to infer that
the driver was avoiding a checkpoint, given the government

                                7
light of his three years’ experience, was reasonably suspicious

that the vehicles’ occupants were engaged in criminal activity.



                               III.

          PROSECUTOR QUESTIONING DURING CROSS-EXAMINATION

     The next issue before us is whether prosecutor questions

posed during cross-examination prejudiced Lopez’s rights to a

fair trial, rendering the district court’s denial of Lopez’s

mistrial motion in error. We review a district court’s denial of

motions for mistrial for abuse of discretion. United States v.

Hernandez-Guevara, 162 F.3d 863, 869 (5th Cir. 1998), cert.

denied, 119 S. Ct. 1375 (1999).

     The questions at issue came at the end of the prosecutor’s

cross-examination:

     Q:    Were you read your rights when you were arrested?
           Defense Counsel:     Objection, Your Honor, completely
                                irrelevant.
           The Court:           Sustained.
     Q:    Were you arrested?
     A:    By immigration, yes.
     Q:    And you asked to speak to a lawyer right away, didn’t
           you?
           Defense Counsel:     Objection, Your Honor, violates –
           The Court:           Sustained.
     Q:    Did you have occasion to tell the border patrol what
           you told us in court today?
           Defense Counsel:     Objection, Your Honor. May we
                                approach, please?
           The Court:           No. Objection sustained.




introduced no evidence that it was unusual to see traffic on that
road at that time. Here, the vehicles’ Austin registration
contributed to the inference that a checkpoint was being avoided.
Officer Meredith also testified that there “wasn’t any other
traffic on the highway that time of night.”

                                  8
After defense counsel moved for a mistrial, which the court

denied, the prosecutor stated he had no further questions.

     Lopez argues that these questions were in clear violation of

the principles laid out in Doyle v. Ohio, 426 U.S. 610 (1976), in

that they represented the use of Lopez’s post-arrest, post-

Miranda1 silence for impeachment purposes. That objections were

sustained before Lopez could respond is of no moment because the

mere posing of these questions seriously undermined Lopez’s

defense. As a result, the prosecutor’s behavior did not

constitute harmless error.

     The Government contends first that the questions did not

violate Doyle. They were intended to show Lopez was not

unsophisticated, as his testimony suggested, or were ambiguous in

that they did not clearly regard Lopez’s post-arrest, post-

Miranda silence. The Government further argues that even if the

questions violated Doyle, mere posing of them was harmless error.

     In an apparent attempt to ensure the prosecutor adhered to

the Doyle rule, defense counsel filed a motion in limine, which

requested that the court order the prosecutor “to refrain from

commenting before the jury on, alluding before the jury to, or

eliciting testimony from any of the witnesses regarding

Defendant’s post-arrest silence or his failure to make a post-

arrest sworn statement.” Granting this motion, the court allowed

the prosecutor to raise only Lopez’s statement that he was in the

country illegally. In light of this order, rather than assessing

     1
         Miranda v. Arizona, 384 U.S. 436 (1966).

                                 9
the prosecutor’s behavior within a Doyle framework, we analyze

the challenged questions in terms of the closely analogous claim

of prosecutorial misconduct. Cf. Greer v. Miller, 483 U.S. 756

(1987) (considering whether defendant was denied a fair trial due

to prosecutorial misconduct after determining that no Doyle

violation had occurred).2

     The Supreme Court has made clear that the “touchstone of due

process analysis” in cases involving prosecutorial misconduct is

the fairness of the trial. See Smith v. Phillips, 455 U.S. 209,

219 (1982). Accordingly, our “task in reviewing a claim of

prosecutorial misconduct is to decide whether the misconduct

casts serious doubt upon the correctness of the jury’s verdict.”

United States v. Carter, 953 F.2d 1449, 1457 (5th Cir.), cert.

denied sub nom., Hammack v. United States, 504 U.S. 990 (1992).

Our inquiry proceeds in two steps. First, we must decide whether

the prosecutor’s questions were improper. See United States v.

Gallardo-Trapero, 185 F.3d 307, 320 (5th Cir. 1999); United

States v. Munoz, 150 F.3d 401, 414 (5th Cir. 1998), cert. denied,

119 S. Ct. 887 (1999). If the questions are found to be improper,

we next assess whether they prejudiced Lopez’s substantive

rights. See Gallardo-Trapero, 185 F.3d at 320; Munoz, 150 F.3d at

     2
        In citing Greer, we do not intend to suggest that we have
determined that the prosecutor’s questioning of Lopez
constituted, or did not constitute, a Doyle violation. We only
note, as did the Supreme Court in Greer, 483 U.S. at 765, that
prosecutorial questioning regarding a defendant’s post-arrest
silence may operate to deprive that defendant of a fair trial.
Because Lopez argues that the prosecutor’s questions prejudiced
his rights to a fair trial, we consider his claim to include a
claim of prosecutorial misconduct.

                               10
415. Reversal is appropriate only where the questions “taken as a

whole in the context of the entire case” do not constitute

harmless error. Id. (quoting United States v. Nixon, 777 F.2d

958, 972 (5th Cir. 1985)). In assessing whether the questions

were harmless, we consider “(1) the magnitude of the [questions’]

prejudice, (2) the effect of any cautionary instructions given,

and (3) the strength of the evidence of the defendant’s guilt.”

United States v. Tomblin, 46 F.3d 1369, 1389 (5th Cir. 1995)

(quoting United States v. Simpson, 901 F.2d 1223, 1227 (5th Cir.

1990)).

     We find that each of the prosecutor’s questions at issue

here was improper. The Government conceded at oral argument that

the question of whether Lopez asked to see his lawyer right away

was improper. The questions posed also clearly violated the

court’s in limine order in that they alluded to, and attempted to

elicit information regarding, Lopez’s post-arrest silence. We do

not find persuasive the Government’s argument that the

prosecutor’s question as to whether Lopez had had occasion to

tell his story to the Border Patrol officers was ambiguous as to

the time to which it referred. Officer testimony had already

established that upon declaring he was in the country illegally,

Lopez was immediately arrested, put into the officers’ vehicle,

and read his rights. Thus, the only time to which this question

could conceivably refer was the post-arrest period during which

Lopez was still in the company of the Border Patrol. Cf. United

States v. Rodriguez, 43 F.3d 117, 123 (5th Cir.), cert. denied,


                               11
515 U.S. 1108 (1995) (noting, in concluding harmless error, that

prosecutor’s question made no reference to the defendant’s

constitutionally protected post-arrest silence and that the

record showed no Miranda warnings).

     We do not find the evidence against Lopez to be

overwhelming. The case turned entirely on the knowledge element

of the charged crime. The Government’s position was that Lopez’s

story was implausible, and that he either knew he was

transporting marijuana or was deliberately ignorant of the facts,

given, for example, the odor of marijuana in the car. No evidence

was presented that Lopez opened the trunk. Officers testified

they could identify the smell of marijuana only because of their

training. Lopez’s sole defense was that he had no knowledge. He

had merely agreed to drive a car for another person in return for

assistance across the river and to Austin. Three hours after his

arrest, when approached by drug enforcement agents and asked

about the drugs, he responded, “What marijuana?”

     The magnitude of the prejudicial effect of the prosecutor’s

questions “is tested by looking at the prosecutor’s remarks in

the context of the trial in which they were made and attempting

to elucidate their intended effect.” United States v. Fields, 72

F.3d 1200, 1207 (5th Cir.), cert. denied, 519 U.S. 807 (1996).

The trial judge’s assessment of any possible prejudicial effect

carries considerable weight. Munoz, 150 F.3d at 415.

     As mentioned, the prosecutor’s questions came at the end of

his cross-examination of Lopez. Prior questioning focused on


                               12
demonstrating the implausibility of Lopez’s story, with questions

highlighting such things as Lopez’s inability to state the names

of the two individuals he said helped him across the border, gave

him keys to the Cavalier, and asked him to follow a truck to San

Antonio; Lopez’s testimony that he did not bring water with him

on his journey; and his testimony that he did not smell anything

unusual in the car. The jury could have easily understood the

challenged queries as continuing the “implausibility” line of

questions, and as leading to the conclusion that Lopez had

fabricated his entire story for purposes of trial.

     On brief, the Government does not negate that this was the

intended effect. The Government states that the questions were

asked in part to show that Lopez’s “defensive theory had serious

gaps as compared to the evidence already presented to the jury.”

Given that the prosecutor would have ample opportunity to

highlight any inconsistencies in his concluding remarks, “gaps,”

to the extent that they existed, did not need to be highlighted

further by a series of questions in violation of the order

prohibiting reference to Lopez’s post-arrest silence. Rather than

highlighting inconsistencies across witnesses’ testimony, it is

more likely that the purpose of the questioning was to attack the

plausibility of Lopez’s defense by suggesting that his entire

story had been fabricated.

     The Government describes the purpose of the question

regarding whether Lopez requested a lawyer upon arrest as

countering impressions left by his testimony that he was


                               13
unsophisticated and “duped by three nameless individuals” and had

“never smelled marijuana.” Apparently, if Lopez knew enough to

ask for a lawyer, he also knew what marijuana smelled like and

how to avoid being duped by others.3 “Comments that penalize a

defendant for the exercise of his right to counsel and that also

strike at the core of his defense cannot be considered harmless

error.” United States v. McDonald, 620 F.2d 559, 564 (5th Cir.

1980).

     Our prior cases have demonstrated that the type of

prosecutorial behavior reflected in this case has such a

detrimental effect on a defendant’s substantive rights that a new

trial is warranted. See, e.g., United States v. Shaw, 701 F.2d

367, 383 (5th Cir. 1983), cert. denied, 465 U.S. 1067 (1984)

(describing cases in which judgment has been reversed because of

prosecutor use of defendant’s silence). In Shaw, we noted that

     [W]e have reversed when we found that the remark “went to
     the heart of [the defendant’s] sole defense,” where the
     defendant’s defense was “not so implausible as to be
     dismissed out of hand” and evidence of guilt was not
     overwhelming, and where the prosecutor had argued the
     substantive or impeachment possibilities of the testimony,
     or had directly tied the defendant’s silence to the
     implausibility of his defense.

Id.(citations omitted); see also Velarde v. Shulsen, 757 F.2d

1093, 1095 (10th Cir. 1985) (per curiam) (“where the case comes

down to a one-on-one situation, i.e., the word of the defendant

against the word of the key prosecution witness, and where there


     3
        As the Government argued, “Put simply, Appellant did not
know the difference between urban and rural but yet, he knew to
ask for a lawyer.”

                               14
is no corroboration on either side, the importance of the

defendant’s credibility becomes so significant that prosecutorial

error attacking that credibility cannot be harmless beyond a

reasonable doubt”); United States v. Johnson, 558 F.2d 1225, 1230

(5th Cir. 1977) (finding reversal required where testimony

regarding defendant’s post-arrest silence “went to the heart of

the sole defense” of no knowledge of the cocaine found in her

possession).

     Given the magnitude of the prejudicial effect of the

prosecutor’s questions, we do not find the trial judge’s pre-

trial and post-closing-argument statements to the jury sufficient

to render the effect of the prosecutor’s questioning harmless. As

a result, we conclude that the trial judge abused his discretion

in denying Lopez’s motion for a mistrial.



                           CONCLUSION

     Because we find that prosecutorial misconduct prejudiced

Lopez’s rights to a fair trial, we REVERSE the conviction and

REMAND to the district court for a new trial.




                               15
