At a permanent border patrol checkpoint located near the United States-Mexico border, agents discovered thirty-eight pounds of marijuana hidden in the fuel tank of a vehicle driven by the Appellees, Juan Manual Ras-con-Ortiz and Edgar Rascon-Sotelo. Both men were indicted for possession with intent to distribute marijuana in violation of 21 U.S.C. § 841(a)(1), (b)(1)(D) and 18 U.S.C. § 2. The United States appeals the district court order granting the Appellees’ motion to suppress evidence obtained at the checkpoint. We reverse.
I. Background
The relevant facts are as follows. On October 13, 1991, Juan Manual Rascon-Ortiz drove his Mercury Topaz into the permanent border patrol checkpoint located on Highway 54, near Orogrande, New Mexico, roughly forty miles from the Mexico border. Mr. Rascon-Ortiz, accompanied by Mr. Edgar Rascon-Sotelo, stopped as required at the primary inspection area. Border patrol agent Sidney Hooper questioned Mr. Ras-con-Ortiz about his citizenship. According to Agent Hooper’s observations, Mr. Rascon-Ortiz’s hand was shaking badly when he handed Agent Hooper his alien registration card. Agent Hooper then inquired as to Mr. Rascon-Sotelo’s citizenship and Mr. Rascon-Sotelo replied that he was a Mexican citizen and produced a Mexican passport with a visitor’s visa. Mr. Rascon-Sotelo’s hand was also visibly shaking. Due to their nervous behavior, Agent Hooper, who had over eighteen years experience as a border patrol agent, directed the Appellees to secondary inspection while he checked other vehicles which' had stopped behind the Appellees. Appellees were at the primary inspection area for one to two minutes.
Border Patrol Agent Eligió Pena, who was not present during the primary inspection, talked briefly with Agent Hooper before going to the secondary inspection area. Agent Hooper told Agent Pena that he thought they “had something because [the Appellees] were shaking like leaves in the wind.” Agent Pena became more suspicious when he noticed the car was a Mercury Topaz because four similar vehicles manufactured by Ford were found to have contraband hidden in false compartments in their gas tanks during the past six weeks. Without further questioning the Appellees, Agent Pena knelt down and looked under the car with a flashlight and noticed the bolts supporting the gas tank were shiny, indicating someone may have tampered with them. Agent Pena then got on his back and slid under the car to take a closer look. With the aid of a mirror and flashlight, Agent Pena observed that both the *751 bolts supporting the gas tank and the threads of the gas line clamp were shiny and scratched, as if they had recently been removed or replaced. Agent Pena’s brief inspection of the vehicle’s undercarriage at secondary took roughly two minutes.
Based upon his observations under the car and his seven years of experience as a border patrol agent, Agent Pena determined that the gas tank had recently been removed and might contain a false compartment. Agent Pena then brought out a trained dog which alerted on the gas tank, indicating the presence of contraband. 1 The Appellees were advised of their Miranda rights and consented, in writing, to a search of the vehicle. The vehicle was subsequently placed on a ramp and a total of thirty-nine pounds of marijuana were discovered in hidden compartments within the gas tank.
Mr. Rascon-Ortiz and Mr. Rascon-Sotelo were indicted for possession with intent to distribute less than fifty kilograms of marijuana in violation of 21 U.S.C. § 841(a)(1), (b)(1)(D) and 18 U.S.C. § 2. Both Appellees moved to suppress all evidence seized at the border checkpoint, alleging the detention and search were unlawful under the Fourth Amendment. After a pretrial hearing, the district court granted the motion to suppress. Although it was deemed reasonable to refer the Appellees to the secondary inspection area, the district court found the border patrol agents lacked the necessary reasonable suspicion or probable cause to justify the “more intrusive investigative detention in the secondary area,” and, therefore, the agents “exceeded the bounds of what the Fourth Amendment allowed at'that moment.” The United States appeals, asserting that the district court erred in granting the Appellees’ motion to suppress.
II. Legal Analysis
Upon appeal, we consider evidence addressed at a suppression hearing in a light most favorable to the prevailing party.
United States v. Johnson,
The government, alleges that Agent Pena’s visual inspection of the vehicle’s undercarriage was part of a valid customs inspection and did not constitute a search. Moreover, the government alleges the Appellees’ nervous behavior gave rise to a reasonable suspicion that the Appellees were involved in criminal activity. The Appellees contend Agent Hooper violated their Fourth Amendment rights when he directed them to the secondary inspection area. Specifically, the Appellees assert that because they were questioned about their citizenship and immigration status at the primary inspection area, any further detention was invalid as Agent Hooper.lacked probable cause or reasonable suspicion. In order to resolve these allegations, we must first clarify the law concerning primary and secondary inspection areas. 2
A. Detention of Appellees at the Secondary Inspection Area.
Despite numerous recent rulings, there apparently still exists some confusion over the distinction between primary, and secondary inspection areas at border checkpoints.
See, e.g., United States v. Ludlow,
A brief summary of relevant border checkpoint law is necessary in order to clarify Tenth Circuit law. A' detention at a border checkpoint is a seizure under the Fourth Amendment.
4
Martinez-Fuerte,
There are two statements of law in
Martinez-Fuerte
which are especially relevant to our discussion. First, the Supreme Court held- that border patrol agents may direct motorists from the primary inspection area to secondary without individualized suspicion and “have wide discretion in selecting the motorists to be diverted.”
5
Id.
at 563-64,
A routine checkpoint stop must be brief and unintrusive. It generally involves questions concerning the motorist’s citizenship or immigratiqn status, and a request for documentation.
Martinez-Fuerte,
Tenth Circuit law is consistent with
Martinez-Fuerte.
Border Patrol Agents may inspect vehicles at border checkpoints without individualized suspicion and have “virtually unlimited discretion to refer cars to the secondary inspection area” in order to effectuate the inspection.
Sanders,
Thus, any distinction between primary and secondary inspection is meaningless. Border Patrol Agents must limit their inspection to a routine checkpoint stop unless consent, probable cause or reasonable suspicion arises during the stop. Whether the routine checkpoint stop is conducted at primary, secondary, or both is irrelevant to Fourth Amendment concerns.
8
Ludlow,
In the present case, the Appellees’ Fourth Amendment rights were not violated when Agent Hooper directed them to the secondary inspection area. Agent Hooper asked a few preliminary questions at the 'Primary inspection area, and became suspicious upon observing that both Appellees’ hands were shaking nervously. The district court concluded the Appellees’ nervousness constituted suspicious circumstances. We agree and find “the suspicious circumstances ... perceived by the border patrol agent are supported by the facts.”
Sanders,
*754 B. Visual Inspection of Car’s Undercarriage.
The remaining issue is whether Agent Pena violated the Appellees’ Fourth Amendment rights by examining the undercarriage of the car. The district court interpreted Sanders as limiting a border patrol agent to only questioning a motorist at secondary concerning suspicious circumstances and, there- ’ fore, concluded that Agent Pena “leapfrogged the next step in the constitutionally permissible continuum” when he immediately proceeded to search the vehicle rather than question the Appellees. We reverse.
The Sanders opinion focused exclusively on the scope of questioning permissible during a checkpoint stop as that was the issue raised by the case. The emphasis on questioning, however, was not intended to exclude all other nonverbal conduct by border patrol agents. Instead, an agent’s nonverbal conduct during a checkpoint inspection is viewed' under the Fourth Amendment balancing test and ultimate standard of reasonableness.
The Supreme Court has spoken, in general terms, on the extent of nonverbal conduct permissible at a routine checkpoint stop. A routine checkpoint stop includes a visual inspection of the vehicle, but the inspection “is limited to what can be seen without a search.”
Martinez-Fuerte,
Since the Supreme Court has not attempted to define what constitutes an automobile search at a border checkpoint,
See Ortiz,
We find the brief visual examination of the vehicle’s undercarriage was not a search, but part of a valid routine checkpoint stop. Our finding is consistent with the recent Tenth Circuit opinion in
United States v. Gonzalez-Acosta,
Crawling under the vehicle did not significantly add to the intrusiveness of the routine checkpoint stop. Agent Pena’s conduct was no more intrusive than if he had questioned the Appellees concerning the suspicious circumstances. The inspection of the vehicle’s undercarriage lasted less than two minutes and did not involve more intrusive, time-consuming measures such as putting the car on a lift to obtain a better view.
The Appellees urge that the use of a flashlight and mirror to inspect the undercarriage constituted a search. We disagree. “[T]he usé of artificial means to illuminate a darkened area simply does not constitute a search, and thus triggers no Fourth Amendment protection.”
Brown,
Our holding that Agent Pena’s inspection of the vehicle’s undercarriage did not constitute a search is consistent with
United States v. Price,
In summary, the Appellees were not detained at the secondary inspection area in violation of their Fourth Amendment rights but instead were lawfully referred to secondary during the course of a routine checkpoint stop. Furthermore, Agent Pena’s examination of the vehicle’s undercarriage did not constitute a search and thus did not violate the Appellees’ Fourth Amendment rights. Since there is no objection to either the canine inspection or the search of the hidden compartment, we do not address these issues.
We REVERSE the district court and REMAND for further proceedings consistent with this opinion.
Notes
. Agent Pena testified that the Appellees consented to the canine inspection, but the district court did not make a factual finding as to this matter. No contradictory evidence was presented as neither Appellee testified at the suppression hearing.
. While the government did not expressly appeal the issue of whether it was proper for border patrol agents to order Appellees to secondary, and the Appellees did not cross-appeal, we will address the issue because it is closely intertwined with the issue raised by the government. As a practical matter, it would be difficult, if not impossible, to address only that conduct by the agents which the government alleges was part of a lawful detention, without addressing other agent conduct during the detention.
. The "reasonable suspicion” standard is an objective test which requires police to have an articulable, individualized, reasonable suspicion that an individual is involved in some criminal activity in order to conduct a valid, investigatory stop of that individual.
See United States v. Espinosa,
. We note this case involves a permanent checkpoint
removed
from the United States-Mexico border, as authorized by 8 U.S.C. § 1357(a)(1) and (a)(3) (1988);
see
8 C.F.R. § 287.1(a)(2) (1992), and, therefore, all references in this opinion to checkpoints refer to checkpoints
not
located on the border! This is an important distinction as a citizen’s Fourth Amendment rights at a checkpoint located on the border, or its functional equivalent, are significantly less than inside the border.
See United States v. Montoya de Hernandez,
.The primary inspection area in
Martinez-Fuerte
involved a visual inspection of cars as they slowed and funneled through the checkpoint. A point agent visually screened the traffic and occasionally referred a vehicle to secondary for questioning, leaving the great majority of vehicles to pass through the checkpoint without questioning or close visual inspection.
Id.
. A "suspicious circumstance” is not equivalent to the "reasonable suspicion" standard.
See Sanders,
. We note' that a routine customs inspection is, in essence, an investigatory stop and therefore, merely satisfying the "reasonable suspicion” standard may only permit agents to conduct a slightly more intrusive stop than is already permitted.
See Martinez-Fuerte,
.Obviously, if a secondary inspection area is such that it causes the detention to exceed a routine checkpoint stop because it is overly intrusive or lengthy, the secondary inspection becomes relevant in a Fourth Amendment analysis; however, the relevancy would still be based upon the reasonableness of the detention as determined by balancing Fourth Amendment interests, and not merely because the detention occurred at secondary.
. The government does not contend, nor did the district court find, that Agent Pena had probable cause or consent when he looked.under the Ap-pellees1 car.
. It is unnecessary for us to address the government’s contention that the Appellees’ nervous behavior gave rise to "reasonable suspicion.”
