F IL E D
                                                                     United States Court of Appeals
                                                                             Tenth Circuit
                                         PUBLISH
                                                                         November 9, 2006
                      U N IT E D ST A T E S C O U R T O F A PP E A L S
                                                                         Elisabeth A. Shumaker
                                                                             Clerk of Court
                                    T E N T H C IR C U IT



 U N ITED STA TES O F A M ER ICA ,

          Plaintiff - Appellee ,

 v.                                                          No. 05-3455

 JO SE ISR AEL C HA V IR A ,

          Defendant - Appellant .



           A PPE A L FR O M T H E U N IT ED ST A T ES D IST R IC T C O U R T
                        FO R TH E D ISTR IC T O F K A N SA S
                           (D .C . N o. 05-C R -40010-JA R )


M elissa Harrison , Assistant Federal Public Defender, (David J. Phillips, Federal
Public Defender, and Ronald W urtz, Assistant Federal Public Defender, on the
briefs), Kansas City, Kansas, for Plaintiff - Appellee.

James A. Brown, Assistant United States Attorney, (and Eric F. M elgren, United
States Attorney, on the brief), Topeka, Kansas, for D efendant - Appellant.


Before K E L L Y , A N D ER SO N , and B EA M , * Circuit Judges.


K E L L Y , Circuit Judge.




      *
      The H onorable C. Arlen Beam, Senior Circuit Judge, United States Court
of Appeals for the Eighth Circuit, sitting by designation.
      Defendant-Appellant Jose Israel Chavira entered a conditional plea of

guilty to counts 1 and 3 of a three-count indictment, reserving the right to appeal

the denial of his motion to suppress. Count 1 charged possession with intent to

distribute approximately four kilograms of a mixture containing cocaine

hydrochloride, 21 U.S.C. § 841(a)(1), (b)(1)(B), 812 and 18 U.S.C. § 2. Count 3

was a forfeiture count. M r. Chavira was sentenced to 57 months in prison and

three years of supervised release on count 1. Our jurisdiction arises under 28

U.S.C. § 1291, and we affirm.




                                     Background

      Shortly after midnight on February 14, 2005, Kansas Highway Patrol

Trooper Craig Phillips (“the trooper”) was patrolling Interstate 70 in Shawnee

County, Kansas, when he observed a truck weaving in and out of an eastbound

travel lane. The trooper stopped the truck and approached its driver and sole

occupant, M r. Chavira. As he began speaking with M r. Chavira, the trooper

noticed several items: a cell phone on the driver’s side visor, an air freshener

hanging from the gear shift, a black duffel bag on the passenger’s side, and a can

of Red Bull (energy drink) on the floor. M r. Chavira explained that he was tired

and had been looking for a place to rest.

      The trooper asked for M r. Chavira’s license, registration and insurance

                                            -2-
documents. He also requested that M r. Chavira exit the vehicle and meet him at

his patrol car. M r. Chavira did so, and the trooper examined the documents w hile

engaging M r. Chavira in conversation about the w eather and his travel plans. M r.

Chavira said that he w as driving from Denver to St. Louis to visit his cousin for a

week. He also told the trooper that he was self-employed as a carpet installer in

Denver but that his partner would be able to handle their commitments while he

was out of town.

      The trooper returned to M r. Chavira’s truck, checking the VIN on the dash.

W ithout asking permission, the trooper also opened the driver’s door of the truck,

checking the VIN on the doorjamb from outside the passenger compartment. The

trooper testified that it was his normal practice to verify that the VIN on the

registration document matched the VINs on the dash and the doorjamb. W hile

matching the VIN on the doorjamb, the trooper noticed a second cell phone on the

floor of the truck. Checking the doorjamb took approximately fourteen seconds.

      The trooper then returned to his patrol car and handed M r. Chavira’s

documents to him. He gave M r. Chavira a warning citation for failing to stay in

his lane and explained this violation to him. The men w ere standing at the

passenger side of the patrol car, with M r. Chavira closer to his truck, and the

trooper behind the opened passenger door of his patrol car. To this point, the

entire encounter had lasted about seven minutes. The trooper testified that M r.



                                         -3-
Chavira’s hands were shaking and he was “quivery.” Although the trooper

acknowledged that it is common for drivers to be nervous when stopped and that

it was a cold night, he thought M r. Chavira was more nervous than most because

his hands continued to shake throughout the encounter.

      The trooper then questioned M r. Chavira further about his travel plans. M r.

Chavira said that he had never been to St. Louis, that his cousin did not know he

was coming, and that he did not know his cousin’s address. The trooper asked if

M r. Chavira had anything illegal in the truck, and M r. Chavira said that he did

not. The trooper then asked about drugs and firearms. M r. Chavira shook his

head vigorously, indicating that he did not, but looked away when asked if he was

carrying cocaine.

      The trooper then asked for permission to search the truck, and M r. Chavira

agreed. Lt. Brinker, another Kansas Highway Patrol officer who had arrived

sometime earlier, stood with M r. Chavira while the trooper conducted the search.

During his twenty-minute inspection, the trooper discovered a lime in the glove

compartment with an “X” shape cut into it, fuel stains on the gas tank, fuel

spillage on the inside of the truck bed, and scratches around the bolts that

fastened the truck’s bed to its frame. He asked for consent to take the truck to the

Highway Patrol garage for further inspection, but M r. Chavira refused.

      The trooper then called for a canine. Almost an hour later, Trooper Scott



                                         -4-
M orris arrived with Ike. Ike walked around the truck and alerted, and M r.

Chavira was placed under arrest. A subsequent search of the truck’s fuel tank

revealed eight bricks of cocaine with a combined weight of approximately ten

pounds.

      M r. Chavira moved to suppress the cocaine, contending that the search was

the product of an unlawful detention and that his consent to search was tainted by

the unlawful VIN search. The district court found–and the government does not

dispute–that the VIN search violated the Fourth Amendment. See R. Doc. 27 at

9. 1 However, the district court held that the encounter became consensual after



      1
         According to the district court, “[u]nder United States v. Caro [

(10th Cir. 2001)], Trooper Phillips impermissibly extended the scope of
Chavira’s detention by entering his truck to check a secondary VIN against the
VIN listed on the registration.” R. Doc. 23 at 9. How ever, New York v. Class,

(1986), makes clear that an officer does not enter the passenger
compartment by merely examining the doorjamb V IN plate while standing outside
the vehicle. In Class, the officer opened the door to see if there was a VIN plate
on the doorjamb and, finding none, reached through the open door and moved
papers covering the dashboard VIN. The Supreme Court began by noting that (1)
the officer could law fully require the driver to open the door and exit the vehicle
and (2) he could lawfully approach the car and view the dashboard through the
windshield. Thus, it reasoned, both locations are “ordinarily in plain view of
someone outside the automobile,” and not subject to a reasonable expectation of
privacy. 

(emphasis added). The Court cautioned that “[i]f
the VIN is in the plain view of someone outside the vehicle, there is no
justification for governmental intrusion into the passenger compartment to see it.”

However, the intrusion into the passenger compartment to move the
papers was reasonable because the VIN was not in plain view either on the
dashboard or the doorjamb. 

       In Caro, we held that “where the dashboard VIN plate is readable from
outside the passenger compartment, that VIN matches the VIN listed on the

                                        -5-
the trooper returned M r. Chavira’s documents and issued him the warning

citation 2 and that the consent to search was sufficiently attenuated from the search

in question to remove any taint. Accordingly, the court denied the motion to

suppress. On appeal, M r. Chavira contends that (1) the trooper unreasonably

detained M r. Chavira after completing the traffic stop and did not permit him to

leave, rendering any consent the fruit of an unlawful detention, (2) the trooper

lacked reasonable suspicion to question M r. Chavira after returning his

documents, and (3) all evidence recovered from the truck must be suppressed as

fruit of an unlawful search of the car for the VIN .




                                     Discussion

      W hen reviewing the denial of a motion to suppress, we accept the district



registration, and there are no signs the plate has been tampered with, there is
insufficient cause for an officer to extend the scope of a detention by entering a
vehicle’s passenger compartment for the purpose of further examining any 

(emphasis added). In light of this holding and the Supreme
Court’s reasoning in Class, we believe it is clear that Caro applies only when (1)
the officer has verified the dashboard or doorjamb V IN from outside the
passenger compartment and (2) the officer nevertheless physically enters the
passenger compartment to check the VIN. There is no unlawful detention under
Caro if the officer remains physically outside the car when he examines the V IN
on the dashboard, the doorjamb, or both.
      2
         The district court also found that the trooper had reasonable suspicion to
continue questioning M r. C havira after returning his documents. Because we
conclude that the encounter was consensual, we need not review this alternate
basis for the district court’s decision.

                                         -6-
court’s factual findings unless clearly erroneous, and we view the evidence in the

light most favorable to the government. United States v. Cheromiah, 

, 1220 (10th Cir. 2006). However, we review de novo the ultimate

determination of reasonableness under the Fourth A mendment because that is a

legal conclusion. 

are largely undisputed. M r. Chavira bears the

burden of establishing a Fourth Amendment violation. 

Detention

      M r. Chavira argues that the law ful traffic stop ended when his documents

were returned, and he w as thereafter unlawfully detained because “[t]he trooper’s

actions and continuous questioning gave no signal to [him] that he actually had

permission [to] continue on his way.” Aplt. Br. at 13. This detention, he

contends, tainted his consent to search. The government concedes that M r.

Chavira was detained when he was stopped, but it maintains that the encounter

became consensual once the trooper returned M r. Chavira’s documents and issued

him a warning citation.

      It is clear that a “seizure that is justified solely by the interest in issuing a

warning ticket to the driver can become unlawful if it is prolonged beyond the

time reasonably required to complete that mission.” Illinois v. Caballes, 

, 407 (2005). Accordingly, we have held that a “driver must be permitted to

proceed after a routine traffic stop if a license and registration check reveal no



                                           -7-
reason to detain the driver unless the officer has reasonable articulable suspicion

of other crimes or the driver voluntarily consents to further questioning.” United

States v. W est, 

, 1176 (10th Cir. 2000).

      However, a traffic stop may become a consensual encounter, requiring no

reasonable suspicion, if the officer returns the license and registration and asks

questions without further constraining the driver by an “overbearing show of

authority.” 

officer has returned the driver’s documents, further

questioning amounts to an unlaw ful detention only if the driver has objectively

reasonable cause to believe that he is not free to leave. See United States v.

Shareef, 

, 1501 (10th Cir. 1996).

      W e have held that the return of documents is not sufficient to transform a

detention into a consensual encounter if the totality of the circumstances gives the

driver an objectively reasonable basis to believe he is not free to go. See United

States v. M anjarrez, 

, 885-86 (10th Cir. 2003). Such a reasonable

belief may be supported by the presence of more than one officer, the display of a

weapon, the physical touching of the detainee, the officer’s use of a commanding

tone of voice, and the officer’s use of intimidating body language. See, e.g.,

United States v. Bustillos-M unoz, 

, 515 (10th Cir. 2000).

      Considering the totality of the circumstances, the district court’s factual

findings do not suggest a coercive show of authority. It is true that more than one



                                         -8-
officer w as present and that M r. Chavira was not told that he was free to leave.

However, the other officer stayed in his patrol car until after the trooper obtained

consent to search and the other officer’s presence alone would not indicate to a

reasonable person that he was not free to leave. Advising a defendant that he is

free to leave is not an essential prerequisite for a consensual encounter, let alone

a voluntary consent to search. See, e.g., Ohio v. Robinette, 

, 39-40

(1996); United States v. Bradford, 

, 1158 (10th Cir. 2005); United

States v. Elliott, 

, 814 (10th Cir. 1997). Significantly, from the time

the trooper resumed questioning M r. Chavira about his travel plans until the time

he obtained consent to search, M r. Chavira’s path to his vehicle was unobstructed

and the trooper was separated from him by the open patrol car door. On this

record, we must hold that M r. Chavira had no objectively reasonable belief that he

was not free to leave, and thus his subsequent consent to search was not the

product of an unlawful detention.

B.    The VIN Search 3

      M r. Chavira also argues that the cocaine found in his gas tank is the fruit of

the search of his vehicle, specifically the inspection of the VIN located on the



      3
        The government argues that M r. Chavira did not preserve this issue for
review. In the district court, he objected to the VIN search and claimed that the
“information” gained after it was the “fruit of this illegality.” The district court
apparently considered the issue adequately raised because it ruled on it. W e
agree.

                                         -9-
doorjamb. He maintains that his consent to search did not purge that taint. The

government, while conceding that the search was unlawful, as above noted,

contends that M r. Chavira cannot rely upon the fruit of the poisonous tree

doctrine because he has failed to demonstrate a nexus between the inspection of

the VIN located on the doorjamb and the evidence he now seeks to suppress. W e

agree. Evidence will not be suppressed as fruit of the poisonous tree unless an

unlawful search is at least the but-for cause of its discovery. Hudson v.

M ichigan, 

, 2164 (2006). Even then, causation is often so

attenuated that suppression is not justified. Id.; W ong Sun v. United States, 

, 487-88 (1963). W e have described the but-for relationship as a “factual

nexus between the illegality and the challenged evidence.” United States v.

Nava-Ramirez, 

, 1131 (10th Cir. 2000). To establish the factual

nexus, at a minimum, “a defendant must adduce evidence at the suppression

hearing showing the evidence sought to be suppressed would not have come to

light but for the government’s unconstitutional conduct.” 

no such evidence here. During a lawful stop and in the midst of a

lawful VIN check on the dash, the trooper opened the door of M r. Chavira’s truck

and checked the VIN on the doorjamb. The doorjamb inspection lasted fourteen

seconds. It uncovered no contraband, and the second cell phone discovered by

the trooper during that time has no demonstrated connection to what occurred



                                        - 10 -
next. 4 M r. Chavira was not confronted with the fruits of that search or questioned

about anything that it revealed. There is no indication that the trooper would not

have requested or obtained consent to search the truck but for the inspection of

the VIN on the doorjamb. W e may not suppress evidence without but-for

causation. See 

(“[B]ut-for causality is . . . a necessary

. . . condition for suppression.”).

      A FFIR ME D.




      4
         M r. Chavira contends that the trooper “testified that the second cell phone
is what heightened his suspicion . . . .” Aplt. Reply Br. at 8. In fact, the trooper
testified that his suspicion that M r. Chavira might have something illegal in his
truck was based on (1) M r. Chavira’s explanation that he was going to St. Louis
because “he had a slow down at work, but yet his partner was still at home
working,” (2) the Red Bull, the M cDonald’s cup and the bag of food, “which led
me to believe that he [w as] making a nonstop trip,” (3) the air freshener because
“air fresheners are used . . . to cover odors of drugs,” (4) the two cell phones, and
(5) the nervousness M r. Chavira exhibited throughout his interaction with the
trooper. R. Vol. II at 97-98. The trooper further testified that his suspicion was
heightened when M r. Chavira revealed that he did not know where his cousin
lived and that his cousin did not know that he was coming to visit. 

The district court did not believe that the trooper’s discovery of a second cell
phone was the but-for cause of his decision to ask to search the truck. Viewing
the evidence in the light most favorable to the government, as we must,

, we likewise conclude that the second cell phone
was not the but-for cause of the vehicle search.

                                        - 11 -