United States v. Ramirez

FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA, 

Plaintiff-Appellee,

v. No. 05-50165

RAMON RAMIREZ, aka Monserrat

Meza-Ramirez, aka Natividad  D.C. No.

CR-04-01054-ER-5

Ramirez, aka Manuel Clavo-

Barraza, aka Natividad Vidana

Ramirez,

Defendant-Appellant.



UNITED STATES OF AMERICA,  No. 05-50181

Plaintiff-Appellee,

v.  D.C. No.

CR-04-01054-ER-4

JAVIER BELTRAN,

OPINION

Defendant-Appellant.



Appeal from the United States District Court

for the Central District of California

Edward Rafeedie, District Judge, Presiding

Argued and Submitted

August 17, 2006—Pasadena, California

Filed January 16, 2007

Before: Alex Kozinski, Diarmuid F. O’Scannlain, and

Jay S. Bybee, Circuit Judges.

Opinion by Judge O’Scannlain;

Concurrence by Judge Kozinski

533

UNITED STATES v. RAMIREZ 537

COUNSEL

Craig A. Harbaugh, Deputy Federal Public Defender, Los

Angeles, California, argued the cause for the defendants-

appellants. Maria E. Stratton, Federal Public Defender, and

Sean K. Kennedy, Deputy Federal Public Defender, were on

the briefs for Defendant-Appellant Beltran. Brad D. Leven-

son, Deputy Federal Public Defender, was on the reply brief.

Jerald Brainin, Los Angeles, California, filed a brief for

Defendant-Appellant Ramirez.

Gonzalo P. Curiel, Assistant United States Attorney, Los

Angeles, California, argued the cause for the plaintiff-

appellee. Debra Wong Yang, United States Attorney, and

Thomas P. O’Brien, Assistant United States Attorney, were

on the brief.

538 UNITED STATES v. RAMIREZ

OPINION

O’SCANNLAIN, Circuit Judge:

In this criminal appeal we must decide whether the “collec-

tive knowledge” doctrine justifies a warrantless stop of an

automobile by one officer at the request of another officer

within the same police department.

I

A

This case began with an event in which defendants-

appellants Ramon Ramirez and Javier Beltran were not actu-

ally involved. On July 8, 2004, police officers in Glendale,

California, stopped a Mercury Mountaineer with a California

license plate no. 560A975. Its driver was arrested. Officer

Kim Lawrence, a 14-year veteran of the Glendale Police

Department, ran her drug-detecting dog along and through the

vehicle, and the dog alerted to the scent of narcotics. Inside

the vehicle the police found a sophisticated secret compart-

ment in the rear cargo area that could be accessed by an elec-

tronic release located at the vehicle’s front center console.

Sergeant Jack Meier, head of the department’s vice/narcotics

detail, and Officer Joseph Allen, a 14-year veteran of the

department, witnessed the search.

B

Ramirez and Beltran came to the attention of the Glendale

Police Department on July 20, 2004 when officers were con-

ducting surveillance at a residence located on Brussels Ave-

nue in Los Angeles. Led by Sergeant Meier, the officers

observed the same Mercury Mountaineer leave that residence.

It was driven by Beltran, while Ramirez sat in the passenger

seat. Officer Allen noted that the Mountaineer was registered

to another individual at a North Hollywood address; accord-

UNITED STATES v. RAMIREZ 539

ing to Allen’s written declaration, he believed the vehicle was

so registered “to avoid detection by law enforcement while

drug trafficking.” Officers Lawrence and Allen followed the

vehicle as it traveled to a parking lot located on Rosecrans

Boulevard in the city of Paramount.

At 12:30 p.m., Officers Lawrence and Allen observed a

second vehicle, a Chevrolet Silverado, arrive at the Rosecrans

parking lot. Two men got out of the Silverado and approached

the Mountaineer; one was carrying what appeared to be a

weighted-down gym bag.1 Ramirez and Beltran met with

these individuals near the front of the Mountaineer. Beltran

then took the gym bag, opened the rear driver-side door, and

placed the gym bag in the Mountaineer. Ramirez entered the

vehicle through that same door as Beltran walked around the

vehicle to enter through the front passenger-side door. Officer

Lawrence then saw the vehicle “rocking back and forth in [a]

manner consistent with someone forcibly moving the vehi-

cle.” The appellants exited the vehicle and assumed their orig-

inal positions—Beltran driving with Ramirez in the passenger

seat.

During the surveillance at the parking lot, Sergeant Meier

received reports from Officers Allen and Lawrence regarding

the gym bag and its placement in the rear area of the Mercury

Mountaineer. Sergeant Meier knew that this is where the

sophisticated hidden compartment had been found on July 8.

He was also told that one of the occupants of the Silverado

had returned to that vehicle carrying a yellow manila-style

envelope or box. At that time, according to his written decla-

ration, Sergeant Meier “formed the opinion that the Mercury

was transporting narcotics in the hidden compartment.”

Surveillance groups including Officer Lawrence followed

both vehicles as they left the parking lot in separate direc-

1

These individuals were Paul Villalba and Leonel Medina. They were

co-defendants with the appellants but are not parties to this appeal.

540 UNITED STATES v. RAMIREZ

tions. At approximately 1:30 p.m., Sergeant Meier issued a

request over the police radio that a uniformed officer make a

“traffic stop” of the Mercury Mountaineer as it was traveling

on the I-5 freeway. His declaration states that he opted for this

tactic “in order to avoid alerting the occupants of the Mercury

of an ongoing drug investigation and for officer safety rea-

sons.”

Officer Daniel Hulben, a 26-year veteran of the department,

responded to Sergeant Meier’s request. Officer Hulben stated

in a written declaration that he “was aware that Sgt. Meier

was the head of a Vice/Narcotics detail, and [Hulben]

believed that [Meier’s] request related to an ongoing narcotics

investigation.” Officer Hulben drove onto the I-5 freeway and

observed the Glendale police surveillance units. Officers in

those vehicles pointed out the Mercury Mountaineer.

Officer Hulben followed the Mountaineer for approxi-

mately half a mile. He observed Beltran, still driving the vehi-

cle, repeatedly looking in the rear-view mirror for up to five

seconds at a time. The vehicle was straddling two lanes with

both passenger-side tires crossing the stripes and box dots.

At 1:36 p.m., Officer Hulben stopped the Mountaineer for

failing to drive within a single lane. See CAL. VEH. CODE

§ 21658. He spoke with Beltran, who produced a Mexican

driver’s license. Officer Hulben then placed Beltran under

arrest for driving without a California license, purportedly in

violation of California Vehicle Code § 12500(a). Three other

uniformed officers arrived to assist Officer Hulben. Ramirez

was not arrested at that time, but he was given a ride to the

police station.

At 2:35 p.m., Officer Lawrence ran her drug-detecting dog

around and through the Mercury Mountaineer. The dog

alerted to the odor of narcotics in the rear interior area of the

vehicle. The police then searched the hidden compartment

and discovered eight kilograms of cocaine.

UNITED STATES v. RAMIREZ 541

C

On August 5, 2004, a federal grand jury returned an indict-

ment against Ramirez, Beltran, and three other individuals.

The indictment charged the appellants with conspiracy to pos-

sess with intent to distribute eight kilograms of a mixture or

substance containing a detectable amount of cocaine, in viola-

tion of 21 U.S.C. § 846. It named the July 20, 2004 incident

as the requisite “overt act” in the conspiracy.

Ramirez and Beltran each filed a motion to suppress the

cocaine found in the vehicle. Senior United States District

Judge Edward Rafeedie conducted a suppression hearing on

October 26, 2004.

The appellants challenged the validity of the traffic stop

and argued that Officer Hulben lacked personal knowledge of

the facts purportedly giving rise to probable cause for an auto-

mobile search. The district court considered the traffic stop

irrelevant; it noted that “the mere fact that this was communi-

cated over the radio to make a traffic stop suggests that it is

not the ordinary type of traffic stop.” Rather, in the court’s

view, the issue was simply whether there existed probable

cause for the search. The court applied the collective knowl-

edge doctrine, and considered the facts known to all of the

officers involved in the investigation and search. Finding

probable cause, the court denied both suppression motions

from the bench. Judge Rafeedie filed a written order on

November 19, 2004.

Thereafter, Ramirez and Beltran reached plea agreements

with the government. They conditioned their guilty pleas on

the opportunity to appeal the district court’s denial of the sup-

pression motions.

The district court sentenced each appellant to 120 months

imprisonment, a five-year term of supervised release, and a

542 UNITED STATES v. RAMIREZ

special assessment of $100. The district court entered its judg-

ment and commitment orders on March 2, 2005.

Ramirez and Beltran filed timely notices of appeal.

II

At the outset, Ramirez and Beltran contend that the exis-

tence of probable cause is irrelevant because the actual or sub-

jective purpose of Officer Hulben’s actions was to make a

“traffic stop” and that stop was invalid because lane strad-

dling is not illegal unless the driver interferes with other vehi-

cles. They also allege—and the government now concedes—

that the arrest of Beltran was improper because his Mexican

driver’s license qualified him to operate a motor vehicle in

California. In their view, the subsequent search of the vehicle

was the result of this improper arrest and, therefore, the

cocaine should be suppressed.

A

[1] We reject the notion that the subjective purpose of Offi-

cer Hulben’s traffic stop renders the probable cause inquiry

irrelevant. The Supreme Court has made clear that an officer’s

subjective thoughts play no role in the Fourth Amendment

analysis. Whren v. United States, 517 U.S. 806, 811-13

(1996). More specifically, the fact that officers acted on one

rationale “would not foreclose the [government] from justify-

ing [the search] by proving probable cause.” Florida v. Royer,

460 U.S. 491, 507 (1983); United States v. Willis, 431 F.3d

709, 715 (9th Cir. 2005) (“Whren stands for the proposition

that if the officers have probable cause to believe that a traffic

violation occurred, the officers may conduct a traffic stop

even if the stop serves some other purpose.”).2 Thus, it does

2

Further, there is no requirement that the traffic violation have been

related to the grounds upon which the officers could have stopped the

vehicle to search for contraband. Devenpeck v. Alford, 543 U.S. 146,

UNITED STATES v. RAMIREZ 543

not matter that Officer Hulben was directed to make a “traffic

stop,” nor does it matter whether he had valid grounds to

make the traffic stop because of lane-straddling. If the officers

had probable cause, then the seizure and search of the vehicle

will be justified.

We also reject the defendants’ argument that the cocaine

must be suppressed because Beltran’s arrest for driving with-

out a California driver’s license was invalid. Although the

government appears to concede that Beltran’s Mexican driv-

er’s license permitted him to operate a motor vehicle in Cali-

fornia, the issue is of no consequence because the arrest was

not a causal factor in the officers’ discovery of the cocaine.

The narcotics squad arrived shortly after the stop. Had Beltran

not been arrested, Officer Hulben could have simply detained

Beltran and Ramirez on the side of the road until the squad—

with their drug-sniffing dog in tow—arrived on the scene.

Thus, the officers would have discovered the drugs even if

Beltran had not been arrested. “[I]f not even the ‘but for’ test

can be met, then clearly the evidence is not a fruit of the prior

Fourth Amendment violation.” 6 WAYNE LAFAVE, SEARCH AND

SEIZURE: A TREATISE ON THE FOURTH AMENDMENT § 11.4(a), at

260 (4th Ed. 2004); see also United States v. Pulliam, 405

F.3d 782, 791 (9th Cir. 2005) (holding that an allegedly

invalid detention “simply did not contribute or lead to” the

discovery of a firearm). The stop and search of the Mercury

Mountaineer was in no way the fruit of Beltran’s arrest; the

search was based on previously gathered information, aimed

at establishing probable cause to search for contraband.

153-54 (2004) (rejecting this Circuit’s previous rule); see also United

States v. Cervine, 347 F.3d 865, 871 n.7 (10th Cir. 2003) (“Although we

can find no opinion that applies the collective knowledge doctrine to jus-

tify a search when the stop was based on an unrelated traffic violation, we

see no reason that the policies underlying the collective knowledge doc-

trine would not support such a use.”).

544 UNITED STATES v. RAMIREZ

B

We must determine, therefore, whether probable cause

existed to search the vehicle. At the heart of that inquiry is the

“collective knowledge” doctrine. Ramirez and Beltran reject

the notion that the stop and search can be justified by proba-

ble cause arising from the collective knowledge of all the offi-

cers involved. As we discuss further below, they would place

two limitations on the doctrine which would render it inappli-

cable here: (1) a “coordinated-investigation” requirement; and

(2) a “minimal communication” requirement. In any case,

they further contend, Officer Hulben conducted only a “traffic

stop” and was not actually motivated by suspicion of drug

trafficking.

The government’s position is that the collective knowledge

of the various officers involved was sufficient to establish

probable cause to believe that the Mercury Mountaineer con-

tained narcotics at the time it was stopped on July 20, 2004.

The government rejects the limitations appellants seek to

place on the collective knowledge doctrine and insists that

courts can look to the facts known by all officers involved,

even if those facts are not communicated to the officer mak-

ing an arrest or stop. The government further urges that we

not ignore the existence of probable cause to stop the vehicle

simply because Officer Hulben sought to establish an alterna-

tive ground for the stop.3

[2] Ramirez and Beltran concede that Sergeant Meier and

his surveillance team had probable cause to search the vehicle

for contraband. Thus, if the facts known by those officers can

be imputed to Officer Hulben, the district court’s denial of the

suppression motions must be affirmed.

3

A district court’s denial of a motion to suppress is reviewed de novo,

while the factual findings underlying the denial of the motion are reviewed

for clear error. United States v. Gust, 405 F.3d 797, 799 (9th Cir. 2005).

UNITED STATES v. RAMIREZ 545

[3] Under the collective knowledge doctrine, we must

determine whether an investigatory stop, search, or arrest

complied with the Fourth Amendment by “look[ing] to the

collective knowledge of all the officers involved in the crimi-

nal investigation although all of the information known to the

law enforcement officers involved in the investigation is not

communicated to the officer who actually [undertakes the

challenged action].” United States v. Sutton, 794 F.2d 1415,

1426 (9th Cir. 1986). See generally 2 WAYNE LAFAVE, SEARCH

AND SEIZURE: A TREATISE ON THE FOURTH AMENDMENT § 3.5

(4th ed. 2004).4

III

Our prior decisions have applied the collective knowledge

doctrine in at least two situations.

A

The first situation is where law enforcement agents are

working together in an investigation but have not explicitly

communicated the facts each has independently learned.

Application of the collective knowledge doctrine has sparked

disagreement in such a circumstance, see Bailey v. Newland,

263 F.3d 1022, 1032 (9th Cir. 2001) (citing an inter-

jurisdictional conflict); United States v. Shareef, 100 F.3d

1491, 1503-04 (10th Cir. 1996) (same), perhaps because no

single law enforcement officer knows all of the facts neces-

sary to establish reasonable suspicion or probable cause, and

thus aggregation of facts is required.

[4] In prior cases, however, we have been willing to aggre-

gate the facts known to each of the officers involved at least

“[w]hen there has been communication among agents.”

4

The collective knowledge doctrine is otherwise known as the “fellow

officer” rule. See, e.g., State v. Soldahl, 331 Or. 420, 426, 15 P.3d 564,

567 (2000).

546 UNITED STATES v. RAMIREZ

United States v. Del Vizo, 918 F.2d 821, 826 (9th Cir. 1990);

accord United States v. Jensen, 425 F.3d 698, 704-06 (9th

Cir. 2005); United States v. Sandoval-Venegas, 292 F.3d

1101, 1105 (9th Cir. 2002). At the same time, we have

applied the collective knowledge doctrine “regardless of

whether [any] information [giving rise to probable cause] was

actually communicated to” the officer conducting the stop,

search, or arrest. United States v. Bertrand, 926 F.2d 838, 844

(9th Cir. 1991) (emphasis added); see also United States v.

Bernard, 623 F.2d 551, 560-61 (9th Cir. 1980) (looking to

collective knowledge “even though some of the critical infor-

mation had not been communicated to” the arresting officer);

Sutton, 794 F.2d at 1426 (same).

[5] Even in this circumstance, the cases suggest a limited

requirement that there be a communication but not necessarily

the conveyance of any actual information among officers.5

This is a sensible rule; the purpose to be served by any

requirement of communication among the officers is simply

to “distinguish[ ] officers functioning as a team from officers

acting as independent actors who merely happen to be investi-

gating the same subject.” United States v. Terry, 400 F.3d

575, 581 (8th Cir. 2005); see also Bernard, 623 F.2d at 561

(“The officers involved were working in close concert with

each other and the knowledge of one of them was the knowl-

edge of all.” (internal quotation marks omitted)).

5

In Bernard, when we said that “some of the critical information had not

been communicated to” the arresting officer, 623 F.2d at 560-61 (empha-

sis added), we were not implying, as the appellants suggest, that other

pieces of information necessarily must have been communicated. Rather,

we were referring to some portion of the facts needed to constitute reason-

able suspicion or probable cause—the arresting officer knew some, but not

all, of the “critical information.” The missing pieces are imputed to him,

so long as he was working with the other officers, even though they were

not communicated.

UNITED STATES v. RAMIREZ 547

B

The facts of this case illustrate a second situation in which

the collective knowledge doctrine applies: where an officer

(or team of officers), with direct personal knowledge of all

the facts necessary to give rise to reasonable suspicion or

probable cause, directs or requests that another officer, not

previously involved in the investigation, conduct a stop,

search, or arrest. The application of the collective knowledge

doctrine to such situations has its roots in numerous decisions

of the Supreme Court and lower courts.

1

In Whiteley v. Warden, 401 U.S. 560 (1971), a county sher-

iff put out a radio bulletin stating that two individuals were

wanted for breaking and entering. The bulletin provided the

suspects’ names, their descriptions, a description of the vehi-

cle they were likely driving, and the amount of money they

had stolen. A patrolman in another police department relied

on such information to make a warrantless arrest of the sus-

pects. Id. at 563-64. Although in Whiteley there was no show-

ing that the sheriff who issued the bulletin had facts sufficient

to establish probable cause to arrest, the Court assumed that

had the contrary been true, the patrolman’s arrest would have

been justified. It stated, “Certainly police officers called upon

to aid other officers in executing arrest warrants are entitled

to assume that the officers requesting aid offered the magis-

trate the information requisite to support an independent judi-

cial assessment of probable cause.” Id. at 568. Although in

Whiteley the bulletin provided factual information to the

arresting officer, the Court’s analysis seemed to take little

account of it.

Then, in United States v. Hensley, 469 U.S. 221 (1985), a

police officer conducted an investigatory stop based upon

another police department’s “wanted flyer.” The flyer was

issued on the basis of articulable facts supporting reasonable

548 UNITED STATES v. RAMIREZ

suspicion; it identified and described Hensley and gave the

date and location of an alleged robbery. 469 U.S. at 223. Cit-

ing Whiteley, supra, the Court explained:

[W]hen evidence is uncovered during a search inci-

dent to an arrest in reliance merely on a flyer or bul-

letin, its admissibility turns on whether the officers

who issued the flyer possessed probable cause to

make the arrest. It does not turn on whether those

relying on the flyer were themselves aware of the

specific facts which led their colleagues to seek their

assistance. In an era when criminal suspects are

increasingly mobile and increasingly likely to flee

across jurisdictional boundaries, this rule is a matter

of common sense: it minimizes the volume of infor-

mation concerning suspects that must be transmitted

to other jurisdictions and enables police in one juris-

diction to act promptly in reliance on information

from another jurisdiction.

Id. at 231 (emphasis deleted and added). The Court did not

emphasize any details of the flyer; it was enough that the offi-

cer who issued the flyer knew facts supporting reasonable

suspicion. Id. at 234. In fact, the Court reversed the Sixth Cir-

cuit, which had rested its holding “on the omission from the

flyer of the specific and articulable facts which led the first

department to suspect [Hensley’s] involvement in a com-

pleted crime.” Id. at 230.

Finally, in Illinois v. Andreas, 463 U.S. 765 (1983), the

Court considered a situation in which a Drug Enforcement

Agency agent, having already identified the illegal contents of

a container, reopened it following the defendant’s arrest but

before obtaining a search warrant.6 The Court rejected a hold-

6

A customs inspector had discovered quantities of marijuana inside a

large metal container, which had been shipped by air to the defendant. 463

U.S. at 767. The DEA agent, subsequently called to the scene, inspected

UNITED STATES v. RAMIREZ 549

ing by the Appellate Court of Illinois “that [the DEA agent’s]

absence when the container was resealed by customs officers

somehow made less than certain his knowledge of the con-

tainer’s contents.” Id. at 772 n. 5. Citing Whiteley, supra, it

explained that “where law enforcement authorities are cooper-

ating in an investigation, as here, the knowledge of one is pre-

sumed shared by all.” Id. The Court did not mention the

substance of any communication from the customs officials to

the DEA agent regarding the contents of the container at the

time it was resealed. But see Bailey, 263 F.3d at 1031 (sug-

gesting that “[t]he facts of [Andreas] indicated that the DEA

agent knew of the contents of the package based on communi-

cations with other members of the investigation”).

2

[6] We have applied the collective knowledge doctrine in

similar circumstances. In Sutton, 794 F.2d at 1425-27, the

case in which we first recognized the collective knowledge

doctrine, we upheld an investigatory stop by a local deputy

sheriff where Customs officials had requested that local law

enforcement officers be dispatched to an airfield known for

narcotics smuggling. In assessing whether there was founded

suspicion of criminal conduct, we “combined” the facts

known to the Customs officials with those known to the dep-

uty sheriff—without discussing what facts, if any, had been

communicated by the former to the latter. Id. at 1427. We

explained that the collective knowledge doctrine applies “al-

though all of the information known to the law enforcement

officers involved in the investigation is not communicated to

the contraband. The container was resealed and then delivered to the

defendant, who was arrested after taking possession of it at his residence.

Id. Although the container was reopened prior to the authorities’ obtaining

a warrant, the Court affirmed the search, holding that “[n]o protected pri-

vacy interest remains in contraband in a container once government offi-

cers lawfully have opened that container and identified its contents as

illegal.” Id. at 771.

550 UNITED STATES v. RAMIREZ

the officer who actually makes the stop,” and we noted that

an officer may act “based in part on information or directions

from other law enforcement officials.” Id. at 1426 (emphasis

added).

Similarly, in United States v. Mayo, 394 F.3d 1271 (9th

Cir. 2005), a police officer received a phone call from a

known informant, a manager at a motel in an area known for

narcotics activity. The motel manager informed the officer of

facts constituting reasonable suspicion: that several vehicles

were parked nearby; that the occupants got out and began

talking; that one of them handed another a package; and that

another wiped down the steering wheel of his vehicle and

walked away from the group. Id. at 1273 & n.1. The officer

then radioed a police dispatcher, who in turn notified another

officer that he should “investigate suspicious narcotics activi-

ty” at the motel. The dispatcher relayed only that directive

and a description of the cars involved. Id. at 1273, 1275 &

n.7. On those facts, we applied the collective knowledge doc-

trine and upheld the second officer’s detention and question-

ing of the defendant. Id. at 1275.

3

Other circuits have applied the collective knowledge doc-

trine in nearly identical factual situations. In United States v.

Rodriguez, 831 F.2d 162 (7th Cir. 1987), agents of the DEA

had reasonable and articulable suspicion to stop the defen-

dant’s vehicle based on prior surveillance of narcotics activ-

ity. The DEA, however, asked local law enforcement to

conduct a “routine traffic stop” for them. Id. at 164. Although

the Seventh Circuit ultimately resolved the case on the basis

of inevitable discovery, id. at 167, it also noted the collective

knowledge doctrine’s application to the case as follows:

[T]he detaining officer had a reasonable basis for

believing the request to be well-founded—even

though she did not personally know the facts giving

UNITED STATES v. RAMIREZ 551

rise to the suspicion. Unlike Hensley, here the auto-

mobile to be stopped with its occupant was pointed

out specifically by the requesting officer, and the

detaining officer knew the requesting officer was

coordinating a large investigation with local agen-

cies. The state trooper was therefore merely acting as

an “extension” or agent of the DEA agent and she

could act on the DEA agent’s suspicions.

Id. at 166.

In United States v. Ibarra-Sanchez, 199 F.3d 753 (5th Cir.

1999), another similar case, a DEA agent observed a beige

van coming and going from a house known for involvement

in narcotics trafficking. At one point, the agent witnessed sev-

eral men loading duffel bags into the van. Id. at 756-57. To

avoid revealing the existence of the investigation to the van’s

occupants, he called the El Paso Police Department to make

a stop of the vehicle. Id. at 757 & n.1. A dispatcher issued a

radio bulletin that a DEA agent had requested assistance in

stopping a beige van because it was possibly transporting

drugs or weapons. A police officer and SWAT team then

stopped the van. Id. at 757. The Fifth Circuit held that the

officers had reasonable suspicion to stop the van because the

DEA agent’s knowledge was imputed to them under the col-

lective knowledge doctrine. Id. at 759-60.

[7] Lastly, in United States v. Burton, 288 F.3d 91 (3d Cir.

2002), a DEA task force used a confidential informant and

surveillance techniques to acquire probable cause to arrest the

defendant for narcotics trafficking. Id. at 97-99. The agents

followed the defendant from the scene of a narcotics transac-

tion, but they requested assistance in stopping his vehicle. A

uniformed police officer responded. Id. at 95. The Third Cir-

cuit held that the information known to the DEA task force

was sufficient; “the arresting officer need not possess an

encyclopedic knowledge of the facts supporting probable

cause, but can instead rely on an instruction to arrest delivered

552 UNITED STATES v. RAMIREZ

by other officers possessing probable cause.” Id. at 99 (cita-

tion omitted). Indeed, the court applied the collective knowl-

edge doctrine without any discussion of what information was

communicated to the arresting officer.

C

The foregoing cases cut against the appellants’ view of the

collective knowledge doctrine. In each case, one officer (or

team of officers) had all of the necessary facts, and thus no

amassing of independently discovered facts was required. In

each case, the officer conducting the stop, search, or arrest

was given little more than an order or request; the investigat-

ing officer or agent simply provided a description of the sus-

pect, thus pointing out who was the target. In none of these

cases did the investigating officer relay to the second officer

the factual basis for his determination that reasonable suspi-

cion or probable cause existed.

[8] Although Ramirez and Beltran concede that an investi-

gating officer need not convey all of the facts known to him,

they nonetheless insist that “the information conveyed to the

[officer conducting the stop, search, or arrest] must relate in

some meaningful way to suspected criminal activity.” Here,

they think probable cause is lacking because Sergeant Meier

relayed only a request for a “traffic stop” and failed to men-

tion anything about its purpose. But placing such a limitation

on the collective knowledge doctrine would go far beyond the

purpose of “distinguish[ing] officers functioning as a team

from officers acting as independent actors who merely happen

to be investigating the same subject.” Terry, 400 F.3d at 581.

Indeed, where one officer directs another to take some action,

there is necessarily a “communication” between those offi-

cers, and they are necessarily functioning as a team. Officer

Hulben was not investigating Ramirez and Beltran indepen-

dently; he acted only because of a communication from a fel-

low officer. See Shareef, 100 F.3d at 1503 n.4 (noting that

“[i]t is well-established that when an order to stop or arrest a

UNITED STATES v. RAMIREZ 553

suspect is communicated to officers in the field, the underly-

ing facts constituting probable cause or reasonable suspicion

need not be communicated”).

It is true that in some of our prior cases the investigating

officer suggested why the defendant should be seized, see,

e.g., Mayo, 394 F.3d at 1273 (noting that the arresting officer

was told “to investigate suspicious activity, possibly involv-

ing narcotics”), but at no time have we suggested that the con-

veyance of such information was affirmatively required.7

Ramirez and Beltran suggest no possible rationale for impos-

ing that kind of requirement, and none is apparent to us. Had

Sergeant Meier said explicitly that Ramirez and Beltran were

suspected of narcotics activity, such information would not

have brought Officer Hulben any closer independently to

knowing facts sufficient to constitute probable cause. We

would still have to impute facts known only to Sergeant Meier

and his team.

Moreover, there is good reason to reject such a proposed

limitation:

The accepted practice of modern law enforcement is

that an officer often makes arrests at the direction of

another law enforcement officer even though the

arresting officer himself lacks actual, personal

knowledge of the facts supporting probable

cause. . . .

7

To the extent there was a substantive communication at issue in our

prior cases, we suggested only that such communication was sufficient,

not necessary, to invoke the collective knowledge doctrine. See Jensen,

425 F.3d at 704-06; United States v. $129,727.00 U.S. Currency, 129 F.3d

486, 489 (9th Cir. 1997); United States v. Valencia, 24 F.3d 1106, 1108

(9th Cir. 1994); Bertrand, 926 F.2d at 844. In fact, we made this explicit

in Bernard. See 623 F.2d at 561 (“We do not find, however, that this is

required, particularly where, as here, the agents were working in close

concert.”). Thus, we cannot agree with the district court’s analysis in

United States v. Newman, 265 F. Supp. 2d 1100, 1106-08 (D. Ariz. 2003).

554 UNITED STATES v. RAMIREZ

. . . The rule exists because, in light of the com-

plexity of modern police work, the arresting officer

cannot always be aware of every aspect of an inves-

tigation; sometimes his authority to arrest a suspect

is based on facts known only to his superior or asso-

ciates.

Jensen, 425 F.3d at 704-05 (citations and internal quotation

marks omitted). The Supreme Court has shared these con-

cerns, specifically endorsing our view “ ‘that effective law

enforcement cannot be conducted unless police officers can

act on directions and information transmitted by one officer

to another and that officers, who must often act swiftly, can-

not be expected to cross-examine their fellow officers about

the foundation for the transmitted information.’ ” Hensley,

469 U.S. at 231 (quoting United States v. Robinson, 536 F.2d

1298, 1299 (9th Cir. 1976)).

Accordingly, we reject the appellants’ view of the limita-

tions on the collective knowledge doctrine.8

IV

[9] We are satisfied that the collective knowledge doctrine

includes no requirement regarding the content of the commu-

nication that one officer must make to another. Where one

8

Ramirez and Beltran also suggest that to invoke the collective knowl-

edge doctrine, “all officers must be members of a coordinated criminal

investigation.” Of course, Officer Hulben clearly was part of a coordinated

effort—he acted on a request from Sergeant Meier. But their argument

seems to go further. They say that collective knowledge cannot apply

because “Officer Hulben did not participate in any way with either the sur-

veillance of [Appellants] or the Mountaineer. In fact, Officer Hulben was

not even assigned to the narcotics division; he worked as a motor officer

in the traffic division for the past 15 years.” This argument is without

merit, and it clearly conflates the two situations we distinguished above.

There is no requirement that Officer Hulben have been connected to or

involved in the prior investigation. See, e.g., Mayo, 394 F.3d at 1273-75.

UNITED STATES v. RAMIREZ 555

officer knows facts constituting reasonable suspicion or prob-

able cause (sufficient to justify action under an exception to

the warrant requirement), and he communicates an appropri-

ate order or request, another officer may conduct a warrant-

less stop, search, or arrest without violating the Fourth

Amendment. Accordingly, appellant’s convictions are

AFFIRMED.

KOZINSKI, Circuit Judge, concurring:

I join Judge O’Scannlain’s opinion, but write separately to

emphasize what this case is not about. This is not a case

where the investigating officers ordered a fellow officer to

conduct a traffic stop because they lacked probable cause for

a narcotics stop. Sergeant Meier had probable cause to order

a narcotics stop, and that’s exactly what he did. He requested

that the arresting officer make it look like a “traffic stop” as

a safety measure, to prevent the risk of harm to a lone officer

trying to make a narcotics arrest before backups could arrive

on the scene. But that did not change the nature of the stop,

which remained—in substance—a narcotics stop.

Concern for the officer’s safety was entirely justified

because the evidence suggested that the suspects were sea-

soned drug traffickers with access to sophisticated equipment

to ply their trade. It was not unreasonable for Sergeant Meier

to fear that the suspects might use force against the officer

who made the stop, had they realized the real reason for it.

Thus, disguising the stop as a “traffic stop” was a valid law

enforcement tactic calculated to ensure an officer’s safety.

The case would, of course, be quite different if an officer who

had no probable cause or reasonable suspicion were to con-

duct (or direct another officer to conduct) a traffic stop in the

hope of finding something illegal or delaying the suspect.

That kind of pretextual traffic stop is clearly prohibited by the

556 UNITED STATES v. RAMIREZ

Fourth Amendment. See United States v. Wallace, 213 F.3d

1216, 1220-21 (9th Cir. 2000).