*

 This order is not binding precedent, except under the doctrines of law of

the case, res judicata, and collateral estoppel. The court generally disfavors the

citation of orders; nevertheless, an order may be cited under the terms and

conditions of 10th Cir. R. 36.3.

** After examining the briefs and the appellate record, this three-judge

panel has determined unanimously that oral argument would not be of material

assistance in the determination of this appeal. See Fed. R. App. P. 34(a); 10th

Cir. R. 34.1(G). The cause is therefore ordered submitted without oral argument.

F I L E D

United States Court of Appeals

Tenth Circuit

December 6, 2005

Clerk of Court

UNITED STATES COURT OF APPEALS

TENTH CIRCUIT

UNITED STATES OF AMERICA,

Plaintiff-Appellee, No. 05-2119

v. (D. of N.M.)

GABRIEL GUILLEN-ZAPATA,

Defendant-Appellant.

(D.C. No. CR-03-210-JP)

ORDER AND JUDGMENT*

Before KELLY, O’BRIEN, and TYMKOVICH, Circuit Judges.** 

Defendant-Appellant Gabriel Guillen-Zapata, a Mexican citizen without

immigration documents, was apprehended in New Mexico near the border

between the United States and Mexico driving a vehicle transporting 1,650

pounds of marijuana. Guillen-Zapata pled guilty in federal district court in the

District of New Mexico to three counts: (1) conspiracy to possess marijuana with
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the intent to distribute in violation of 21 U.S.C. §§ 841(a)(1)(A), (b)(1)(A) and

846; (2) possession with intent to distribute marijuana in violation of 21 U.S.C.

§§ 841(a)(1) and (b)(1)(B); and (3) being found in the United States after having

been deported as an alien convicted of an aggravated felony in violation of

8 U.S.C. §§ 1326(a)(1), (a)(2), and (b)(2). Guillen-Zapata appeals the denial of

his motion to suppress statements and physical evidence. He argues that the

district court erred in finding the Border Patrol agents possessed reasonable

suspicion to stop his vehicle and contends that all evidence related to the stop

should have been suppressed as fruit of the poisonous tree. 

We take jurisdiction pursuant to 28 U.S.C. § 1291 and AFFIRM.

I. Background

The Birchfield area is a five to seven mile stretch of desert in southern New

Mexico, which runs along the Mexican border to the south and New Mexico

Highway 9 to the north. Throughout the Birchfield area, Highway 9 parallels the

border at a distance of 600 yards at its closest point and one mile at its farthest

point. There are no ports of entry within the Birchfield area, and the nearest ports

are approximately forty miles in either direction. There are no businesses or

structures in the area and no paved roads except Highway 9. A number of illegal

entries had been reported in the area in the three weeks prior to the traffic stop at
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issue, and at least ten drug seizures had been conducted in the area within the

three preceding years.

On December 19, 2002, at approximately 7:30 p.m., a vehicle sensor was

triggered in the Birchfield area. The sensor had been placed between Highway 9

and the Mexican border at a point where the distance between the highway and

border was approximately 600 yards. There was a dirt road running north and

south that crossed Highway 9 at that point. The sensor was designed to detect

vehicles driving off-road between the border and Highway 9, but it was possible

to avoid the sensor by staying on the dirt road. Approximately an hour before the

sensor’s activation, Border Patrol agents had driven along the sensor area parallel

to Highway 9 and marked out a path with their own tire tracks. That way, if

another vehicle crossed their tracks afterward, they would be able to tell. 

When this sensor was activated, Border Patrol Agent Juan Francisco

Jimenez and his partner were parked about a mile west of the sensor’s location. 

Officer Jimenez and his partner waited two or three minutes after hearing the

alarm so they would not “spook” the vehicles that may have activated the sensor. 

Then, they moved up closer to the highway in order to see whether any vehicles

had driven past. They observed the taillights of a vehicle that had just passed

their position heading westbound on Highway 9. Agent Jimenez pulled onto the

highway, radioed the information to other Border Patrol agents, and headed east
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toward the sensor. As he did so, he saw the headlights of a second westbound

vehicle approaching. Agent Jimenez identified the second vehicle, which was

following closely behind the first, as “some type of utility truck.” Tr. at 17. The

two vehicles were headed away from the sensor, and the direction and time frame

of both vehicles was consistent with having activated the sensor. 

Agent Jimenez arrived at the sensor, having seen no other vehicles on the

road between his initial point of observation and the sensor location. He saw

fresh vehicle tracks of two or more vehicles leading from the sensor’s location up

to Highway 9. The tracks indicated that the vehicles had turned west onto the

highway. After he radioed this information to other Border Patrol Agents, Agent

Kevin McCrary, who was approximately four and half miles west of the sensor

area, radioed back that he saw two “utility trucks like the kind the phone company

uses” headed west approximately three car lengths apart. Tr. at 37. At the time

these two vehicles passed his location, Agent McCrary estimated they were

traveling between sixty and sixty-five miles per hour. 

About seven miles west of the sensor, Border Patrol Agent Richard Duggan

learned of the sensor’s activation and the subsequent reports of fellow agents and

headed east toward the sensor. When he passed two trucks that matched the

descriptions provided by the other agents, Agent Duggan made a U-turn and

headed west behind them. As soon as he did so, the lead truck sped up
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considerably and distanced itself from the trailing truck. Agent Duggan thought

this was suspicious, because, when he had passed them, they were traveling at the

same speed approximately 100 yards apart. He pulled alongside the trailing

vehicle and saw the driver, Guillen-Zapata, wearing a hard hat. Agent Duggan

thought this was suspicious, because he had worked in construction and knew that

hard hats were extremely uncomfortable and usually only worn while at a job site.

At that point, Agent Duggan slowed down and stopped the vehicle. As he

approached the driver’s window, he smelled creosote bush, which indicated that

the utility truck had very recently been driven off-road. Agent Duggan knew that

the only way to activate the sensor was to drive off-road. Agent Duggan asked

the driver, Guillan-Zapata, what his citizenship was, and he responded, “Mexico.” 

Tr. at 47. When asked if he had any immigration documents with him, GuillenZapata answered that he did not. Agent Duggan smelled marijuana coming from

the truck cab and saw wrapped packages behind the front seat, which looked to

him like packages of marijuana. When asked what he was carrying, GuillenZapata responded, “Nothing.” Tr. at 48. Then he changed his answer to say he

did not know. Tr. at 48. Agent Duggan opened one of the side compartments of

the truck and, upon observing more bundles, he radioed ahead to tell other agents

to stop the lead truck. The agents discovered 1,650 pounds of marijuana in
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Guillen-Zapata’s truck and subsequently discovered 1,600 pounds of marijuana in

the lead truck.

The lead truck, which was driven by Erasmo Ruiz-Soto, was pursued by

Border Patrol Agent David Joseph Blea. Ruiz-Soto at first slowed down and tried

to waive the officer past him. When Agent Blea attempted to pull him over, he

sped up and abruptly turned off-road, crashing through a fence and heading south

toward the Mexican border, which was less than a mile away. When his truck

became stuck, he attempted to flee on foot but was apprehended.

Co-defendant Ruiz-Soto filed a motion to suppress physical evidence and

statements relating to his arrest, and Defendant-Appellant Guillen-Zapata later

joined that motion. When it was denied, Guillen-Zapata pled guilty but then

appealed the denial of suppression. He argues that the Border Patrol agents

lacked reasonable suspicion to stop his vehicle and therefore violated his Fourth

Amendment rights.

II. Analysis

The Fourth Amendment requires a finding of reasonable suspicion that

criminal activity may be afoot before conducting roving Border Patrol stops. 

United States v. Gandara-Salinas, 327 F.3d 1127, 1129 (10th Cir. 2003) (citing

United States v. Arvizu, 534 U.S. 266, 273 (2002)). “Although an officer’s

reliance on a mere hunch is insufficient to justify a stop, the likelihood of
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criminal activity need not rise to the level required for probable cause, and it falls

considerably short of satisfying a preponderance of the evidence standard.” Id.

(quoting Arvizu, 534 U.S. at 274). Under this standard, Border Patrol agents may

stop vehicles “if they are aware of specific articulable facts, together with rational

inferences from those facts, that reasonably warrant suspicion” of criminal

activity. Id. (quoting United States v. Monsisvais, 907 F.2d 987, 989–90 (10th

Cir. 1990) (quoting United States v. Brignoni-Ponce, 422 U.S. 873, 884 (1975))).

“A determination that reasonable suspicion exists . . . need not rule out the

possibility of innocent conduct.” Arvizu, 534 U.S. at 277.

The following factors are relevant in determining whether a law

enforcement officer has reasonable suspicion to conduct an immigration stop:

(1) characteristics of the area in which the vehicle is encountered; (2) proximity

of the area to the border; (3) usual patterns of traffic on the particular road;

(4) previous experience of the agent with alien traffic; (5) information about

recent illegal border crossings in the area; (6) the driver’s behavior, including any

obvious attempts to evade officers; (7) aspects of the vehicle, such as a station

wagon with concealed compartments; (8) the appearance that the vehicle was

heavily loaded. Gandara-Salinas, 327 F.3d at 1129–30 (quoting Monsisvais, 907

F.2d at 990 (citing factors listed in Brignoni-Ponce, 422 U.S. at 884–85)).
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In evaluating these factors, courts may not employ a “divide-and-conquer”

approach by evaluating and rejecting each factor in isolation. Arvizu, 534 U.S. at

277. Instead, the ultimate determination of reasonable suspicion depends upon

the totality of the circumstances. Gandara-Salinas, 327 F.3d at 1130. When

making their determination, law enforcement officers may rely on their own

experience and specialized training, and courts must defer to their ability to make

inferences from and deductions about the cumulative information that may elude

an untrained person. See Arvizu, 534 U.S. at 273; United States v. De La CruzTapia, 162 F.3d at 1277–78. 

The ultimate determination of reasonableness under the Fourth Amendment

is a conclusion of law that we review de novo. See De La Cruz-Tapia, 162 F.3d

at 1277. The evidence to support that conclusion, however, must be viewed in the

light most favorable to the prevailing party, and we must accept the district

court’s findings of fact unless they are clearly erroneous. Id. at 1277–78. 

On the facts above, the district court found that the Border Patrol possessed

reasonable suspicion to stop Guillen-Zapata’s vehicle. We are convinced that the

totality of the circumstances supports the district court’s ruling. Conceding only

one factor, Guillen-Zapata attacks the court’s findings on each of the other seven

factors. As explained below, we find his arguments unpersuasive.
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(1) As to the first factor (characteristics of the area in which the vehicle is

encountered), Guillen-Zapata takes issue with the court’s description of the area. 

The court described the Birchfield area as a remote and desolate desert. GuillenZapata argues that this was insufficient to support a conclusion that this factor

weighed against him. However, it clearly must be analyzed in context with the

remainder of the court’s discussion and analysis. Specifically, the judge found

that (I) the area was very near the Mexican border; (ii) no designated ports of

entry were nearby; (iii) it had a history of illegal entries and drug seizures; (iv)

after the sensor was triggered, Border Patrol observed only two vehicles within

the relevant vicinity—those driven by Guillen-Zapata and Ruiz-Soto. These

findings together demonstrate that the area lent itself to illegal border crossings

and that, at least on the night in question, it produced a very narrow pool of

suspects. We are satisfied this factor weighs in the government’s favor.

(2) Guillen-Zapata concedes that the second factor (proximity to the border)

weighs against him.

(3) As to the third factor (usual patterns of traffic on the particular road),

Guillen-Zapata claims that the evidence in the record showed only specific flow

and patterns of traffic during the time period at issue, as opposed to the general

tendencies of traffic in the area. Agent Jimenez testified that he was monitoring

Highway 9 on the evening in question and that only two vehicles (those driven by
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Guillen-Zapata and Ruiz-Soto) passed within proximity to the sensor at the time it

was activated. He also testified that ranchers in the area sometimes used the dirt

road leading onto Highway 9 but that use of the road would not trigger the sensor. 

This testimony weighs against Guillen-Zapata, and no reason exists to believe

generalized evidence would have been more helpful than specific evidence. Thus,

absent any argument that the factor should have pointed in the opposite direction,

we see no reason to reach a different conclusion than the district court reached on

this factor.

(4)–(5) The fourth factor (previous experience of the agent with alien

traffic) and fifth factor (information about recent illegal border crossings in the

area), similarly weigh against Guillen-Zapata. The agents testified to their

involvement with several operations in prior years and to familiarity with illegal

drug runs across the border in the recent past. Guillen-Zapata argues that the

agents should have compared prior arrests to the one at issue to show their

specific knowledge of and experience with particular fact scenarios. However,

their testimony of experience in the same field within the same geographic area is

sufficient, so long as their testimony was credible. Compare United States v.

Gandara-Salinas, 327 F.3d at 1131 (basing its conclusion on similarly generalized

statements that the agent had experience in “narcotics seizures” and that the

highway was a “common route for smuggling undocumented immigrants and
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illegal drugs” across the Mexican border). We generally defer to the district court

on credibility determinations, and the record does not suggest any basis for

concluding its decision was clearly erroneous. 

Guillen-Zapata also argues that the agents’ experience was not extensive

enough. Agent Duggan, who made the traffic stop, had been a Border Patrol

agent in this sector for approximately five years and had helped conduct

approximately six drug seizures within the Birchfield area alone. Three of those

involved Highway 9. Agent Jimenez, who provided Agent Duggan with

information based on his own observations at and near the sensor, had worked in

this Border Patrol sector for approximately six and a half years and, during that

time, had been involved in several drug seizures on Highway 9. As the United

States Supreme Court has made clear, courts should be hesitant to second-guess

law enforcement officers’ ability to detect suspicious conduct when they possess

experience and specialized training in that area. See Arvizu, 534 U.S. at 273; see

also De La Cruz-Tapia, 162 F.3d at 1277–78. We disagree with the defendant’s

suggestion that an agent must be involved in hundreds or thousands of operations

before we will defer to his expertise and agree with the district court that this

record provides sufficient basis for this factor to weigh in favor of the

government. 
1

 On this point, it should be noted that the written order was drafted

pursuant to the judge’s oral statements, which were given in response to specific

oral arguments made by Ruiz-Soto’s attorney.

2

 The issue of probable cause to search the vehicle, based upon the scent of

marijuana and view of wrapped packages in the cab, is separate from the issue of

reasonable suspicion to stop the car in the first place. See Brignoni-Ponce, 422

U.S. at 881–82. Only the latter is challenged in this appeal.

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 (6) As to the sixth factor (the driver’s behavior, including attempts to evade

officers), Guillen-Zapata correctly points out that, when discussing driver

behavior, the court referred only to the truck driven by Ruiz-Soto in its

explanation of this factor.1 However, the judge noted in his fact section that

when Agent Duggan stopped Guillen-Zapata’s vehicle, he knew that (i) there was

a sensor activation; (ii) vehicle tracks indicated westbound traffic; (iii) Border

Patrol agents were monitoring two utility trucks headed westbound on Highway 9;

(iv) his law enforcement presence caused the two vehicles, which were traveling

close together, to greatly increase the distance between them; and (v) GuillenZapata was wearing a hard hat although he clearly was not on a construction site. 

Agent Duggan’s experience in the Border Patrol made him suspicious of the

vehicles’ sudden distancing, and his experience in the construction industry made

him suspicious of someone who was wearing a hard hat when not at work. Given

the testimony presented, the district court’s fact findings are not clearly

erroneous.2
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(7) The seventh factor (aspects of the vehicle, such as a station wagon with

concealed compartments), is no help for Guillen-Zapata. He argues the court’s

finding that the trucks were “utility vehicles” was insufficient to support the

factor relating to covered compartments, because the Border Patrol agents did not

specifically say they were suspicious of the vehicles based on their potential to

hold contraband. We need not state the obvious on every point; Guillen-Zapata’s

vehicle falls squarely within this category.

(8) Finally, as to the eighth factor (the appearance that the vehicle was

heavily loaded), Guillen-Zapata does not put forth any argument to explain why it

should weigh in either direction, given that these were utility vehicles that were

built for heavy loads and thus unlikely to show the weight they were carrying. In

addition, even if this factor were considered to weigh in favor of Guillen-Zapata,

the overwhelming evidence presented by the remaining factors is sufficient to

support reasonable suspicion.

III. Conclusion

In light of the above-stated reasons, we agree with the district court that the

totality of the circumstances supports a finding of reasonable suspicion by the

Border Patrol and conclude that Guillen-Zapata’s Fourth Amendment rights were

not violated. We therefore AFFIRM the decision to deny Defendant-Appellant’s

motion to suppress statements and physical evidence. 
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Entered for the Court

Timothy M. Tymkovich

Circuit Judge