                           In the
 United States Court of Appeals
              For the Seventh Circuit
                        ____________

Nos. 03-2056 & 03-2171
UNITED STATES OF AMERICA,
                                           Plaintiff-Appellee,
                              v.


ARTURO GARCIA PARRA and
MAGDALENA CORREA,
                                      Defendants-Appellants.

                        ____________
          Appeals from the United States District Court
               for the Western District of Wisconsin.
        No. 02-CR-92-C—Barbara B. Crabb, Chief Judge.
                        ____________
    ARGUED MARCH 29, 2004—DECIDED MARCH 29, 2005
                    ____________




 Before CUDAHY, ROVNER, and WOOD, Circuit Judges.
   WOOD, Circuit Judge. After conducting elaborate surveil-
lance, a team of federal, state, and local law enforcement
officials nabbed Nazario Varela, Magdalena Correa, Arturo
Garcia Parra, and Luis Garcia Parra on cocaine trafficking
and possession charges. (In order to keep the two Garcia
Parra brothers straight, we will refer to them using their
first names.) All four were indicted for conspiring to dis-
2                                    Nos. 03-2056 & 03-2171

tribute and possess with intent to distribute in excess of 500
grams of cocaine, in violation of 21 U.S.C. § 846, and for
possessing with intent to distribute in excess of 500 grams of
cocaine, in violation of 21 U.S.C. § 841(a)(1). Varela and
Luis pleaded guilty, but Arturo and Correa went to trial and
were convicted on both counts. The latter two now appeal.
  Arturo has raised challenges to the admission of expert
testimony regarding drug trafficking counter-surveillance
techniques; the sufficiency of the evidence to sustain his con-
viction; and the court’s refusal to reduce his offense level for
having only a minor role in the conspiracy. Correa contends
that the officers lacked probable cause to arrest her, and
therefore the court erred in denying her motion to suppress
evidence found in a search incident to her arrest. In a
supplemental brief, Correa has also argued that her
sentence was unconstitutional under the rule announced in
Blakely v. Washington, 124 S.Ct. 2531 (2004), and now
United States v. Booker, 125 S.Ct. 738 (2005). We affirm the
district court’s judgment of guilt with respect to both
defendants. We order a limited remand with respect to both
of the sentences imposed, in keeping with the procedure
outlined in United States v. Paladino, Nos. 03-2296 et al.,
2005 WL 435430 (7th Cir. Feb. 25, 2005).


                               I
  On June 20, 2002, Murillo Luna, a confidential source,
purchased 55.18 grams of cocaine from Varela at the latter’s
home in Janesville, Wisconsin. Five days later, on June 25,
Luna and Drug Enforcement Administration (DEA)
Special Agent Bill Chamulak, acting in an undercover capac-
ity, returned to Varela’s home to purchase a quarter kilogram
of cocaine. Varela asked Luna and Agent Chamulak to return
in about half an hour. Shortly thereafter, officers observed
Varela removing a white cooler from a brown Cadillac in
front of his house. When Luna and Agent Chamulak re-
Nos. 03-2056 & 03-2171                                      3

turned to the house, they noticed a white cooler with the lid
removed. They purchased 248.3 grams of cocaine from
Varela and then departed. Thirty-five minutes later, the
brown Cadillac returned to Varela’s house and officers saw
an Hispanic man enter the house and then leave after
approximately one minute. They also saw an unidentified
passenger in the vehicle. Surveillance officers followed the
brown Cadillac and observed an Hispanic man and woman
exit and then reenter the vehicle, which was later located at
1503 Porter Avenue in Beloit, Wisconsin. This address was
the residence of Arturo, Luis, and Correa.
  On July 10, 2002 at 11:30 a.m., Agent Chamulak and
Luna returned to Varela’s house to negotiate the purchase
of one more kilogram of cocaine. Varela made a phone call
and instructed Agent Chamulak and Luna to return at 3:00
p.m., because his source had to go to Chicago to obtain the
cocaine. At 12:03 p.m., an officer with the Rock County
State Line Area Narcotics Task Force (SLANT) observed
Luis and Arturo drive away from 1503 Porter Avenue in a
white Cadillac. Six SLANT vehicles and a C-26 military
aircraft followed the white Cadillac from Beloit to Chicago.
Remarkably, the passengers in the Cadillac never noticed
their extensive entourage. Upon arriving in Chicago, they
parked their car and interacted with someone in a silver
car. Luis walked between some buildings with the occupant
of the silver car, while Arturo returned to the white Cadillac
and opened the hood and trunk. Luis then walked around
the car, including the trunk area, and Arturo closed the
hood and trunk. Nineteen minutes after arriving in Chicago,
they departed.
  At about 4:30 p.m., the white Cadillac arrived in Janesville
and parked on Main Street. Arturo and Luis checked some-
thing in the trunk and then walked to the parking lot of a
Quick Stop gas station, with Arturo trailing behind Luis.
Officers observed Arturo standing on the corner of Racine
and Main Streets, repeatedly looking up and down the street
4                                   Nos. 03-2056 & 03-2171

and toward the location of the white Cadillac. Shortly there-
after, Varela, Luna, and Agent Chamulak arrived at the
parking lot of the Mexican supermarket located across the
street from the Quick Stop. Varela got out of the vehicle and
entered the surrounding neighborhood. Nine minutes later,
the same brown Cadillac that was present at the June 25
cocaine sale drove into the Quick Stop parking lot. Luis
approached the brown Cadillac and spoke with someone
inside, later identified as Correa. The brown Cadillac then
drove into the parking lot of the Mexican supermarket.
Agent Chamulak observed Correa seated in the brown
Cadillac, with her attention focused on Luna and Varela
and on Agent Chamulak’s vehicle. Surveillance personnel
observed Varela approach the passenger side of the brown
Cadillac and engage in a conversation with Correa. Varela
later testified that Correa asked him if he had received the
money from the buyer, and when he answered in the nega-
tive she commented, “This is not the way you do the deals.”
  As Varela and Luna walked to the white Cadillac, Correa
pulled out of the parking lot and parked on the same side of
Main Street as the white Cadillac. According to Special
Agent Jerry Becka, this position would have allowed Correa
to monitor the white Cadillac through her rear view mirror.
Varela and Luna opened the trunk of the white Cadillac and
found approximately one kilogram of cocaine there. Officers
promptly arrested Varela, Luis, and Arturo. A minute later,
Special Agent Jeanne Hehr and several other officers
arrested Correa.
  Both Varela and Luis pleaded guilty to both counts of the
indictment. Varela testified for the government at Arturo’s
and Correa’s trial pursuant to his plea agreement. Varela
reported that he worked with Arturo in Janesville and told
Arturo that he needed money. Arturo referred Varela to Luis,
from whom Varela borrowed $2,200. When Varela was un-
able to pay back the money, he agreed to sell cocaine for
Luis. Varela testified that Luis and Correa delivered the
Nos. 03-2056 & 03-2171                                     5

cocaine for the June 20 sale. Luis also provided Varela with
the cocaine for the June 25 sale, using a white cooler. After
this purchase, Correa called Varela to discuss whether he
had obtained the money and his cut of the profits. Finally,
Varela stated that Arturo told him that his brother had
asked him to be at the July 10 transaction because his
brother was afraid that Varela was going to steal the money.
  The district court permitted the government to call Agent
Becka to testify about the modus operandi of drug dealers,
especially the use of counter-surveillance techniques,
rejecting Arturo’s motion in limine seeking to exclude this
testimony. Agent Becka opined that Arturo and Correa
provided counter-surveillance during the July 10 sale. The
government established that Agent Becka had been a DEA
special agent for over 19 years; that he had completed train-
ing at both basic and advanced agent schools and attended
yearly meetings where he learned about the latest tricks of
the drug trade; that he had personally purchased drugs in
an undercover capacity over 125 times and provided sur-
veillance in over 1,000 undercover operations; and that he
had interviewed drug dealers at least 500 times to learn
how they operate. On this basis, the court found Agent Becka
qualified to testify as an expert.
  At the close of the government’s case and again at the end
of trial, Arturo and Correa moved for a judgment of acquit-
tal, which the court denied. The jury returned a verdict of
guilty against both of them on both counts of the indict-
ment. Arturo then objected to the presentence report,
arguing that he should have been given a minor role re-
duction in his offense level computation on the theory that
he had acted only as a lookout during the July 10 sale. The
court refused to make this downward adjustment, adopting
the calculations in the presentence report. Arturo now ap-
peals from his conviction and his sentence, as does Correa.
6                                    Nos. 03-2056 & 03-2171

                              II
                 A. Arturo Garcia Parra
  Arturo first argues that the district court erred in allowing
Agent Becka to testify as an expert witness. He contends
that Agent Becka’s testimony did not satisfy the require-
ments for expert testimony established by FED. R. EVID. 702
and the Supreme Court’s decision in Daubert v. Merrell Dow
Pharm., Inc., 509 U.S. 579 (1993). At this point, Rule 702
has superseded Daubert, but the standard of review that
was established for Daubert challenges is still appropriate.
Under that standard, we review de novo the question
whether the district court properly applied the legal
framework, and we review decisions to admit or exclude
expert testimony under the rule for abuse of discretion. See
United States v. Allen, 269 F.3d 842, 845 (7th Cir. 2001).
  Expert testimony is admissible if offered by “a witness
qualified as an expert by knowledge, skill, experience, train-
ing, or education,” and “if (1) the testimony is based upon
sufficient facts or data, (2) the testimony is the product of
reliable principles and methods, and (3) the witness has
applied the principles and methods reliably to the facts of
the case.” FED. R. EVID. 702. Daubert laid the foundation for
this rule, which was designed to ensure that “any and all
scientific testimony or evidence admitted is not only relevant,
but reliable.” Smith v. Ford Motor Co., 215 F.3d 713, 718
(7th Cir. 2000) (internal quotation marks omitted).
  In applying the rule, we have recognized that “[w]hile
extensive academic and practical expertise in an area is
certainly sufficient to qualify a potential witness as an ex-
pert, Rule 702 specifically contemplates the admission of
testimony by experts whose knowledge is based on experi-
ence.” Id. (internal quotation marks and citations omitted);
see Kumho Tire Co. v. Carmichael, 526 U.S. 137, 156 (1999).
“Thus, a court should consider a proposed expert’s full range
of practical experience as well as academic or technical
Nos. 03-2056 & 03-2171                                       7

training when determining whether that expert is qualified
to render an opinion in a given area.” Smith, 215 F.3d at
718; see also United States v. Conn, 297 F.3d 548, 556 (7th
Cir. 2002) (observing that the Advisory Committee notes to
Rule 702 specifically provide that “[i]n certain fields, exper-
ience is the predominant, if not the sole, basis for a great
deal of reliable expert testimony”).
  The district court here properly applied Rule 702. After
conducting a hearing, the court observed that “the Seventh
Circuit has been extremely liberal in allowing testimony by
police officers and federal agents about the use of counter-
surveillance in drug transactions and about other aspects
of drug transactions.” The court concluded that “Agent Becka
is qualified to testify as an expert about these matters,”
citing his formal training from agent school, including
training in counter-surveillance techniques, his extensive
experience as a DEA special agent, and his involvement in
“many dozens, if not hundreds” of undercover purchases
of controlled substances. On appeal, Arturo counters this
reasoning only with the fact that Agent Becka had never
previously testified as an expert on these matters.
  But there is a first time in court for every expert: the
question is not whether Agent Becka was a professional
witness; it is whether he was an expert on the topic of the
modus operandi of narcotics dealers. The district court was
amply justified in concluding that he was. Compare Conn,
297 F.3d at 556. Officer Becka had the kind of experience,
education, and training that we have recognized in the past
as supporting a finding of expertise. See id.; Allen, 269 F.3d
at 846. On several occasions, we have found that an agent’s
experience qualifies him or her to testify as an expert
regarding drug trafficking counter-surveillance. See, e.g.,
United States v. Sanchez-Galvez, 33 F.3d 829 (7th Cir.
1994); United States v. de Soto, 885 F.2d 354 (7th Cir.
1989). See also United States v. Romero, 189 F.3d 576, 584-
85 (7th Cir. 1999) (stating that “modus operandi evidence
has proved useful in drug trafficking cases,” including testi-
8                                    Nos. 03-2056 & 03-2171

mony “regarding various counter[-]surveillance techniques
used by drug dealers to avoid detection”); United States v.
Brown, 7 F.3d 648, 652 (7th Cir. 1993) (same).
  Arturo seeks to distinguish these cases by arguing that
the jury did not need the agent’s testimony to understand
the case. He urges that the surveillance recordings of the
July 10 transaction allowed the jury to be “in effect an eye-
witness to Arturo’s actions” and thus it “could have deter-
mined by viewing DVD and surveillance tapes the entire
scope of his alleged involvement and determined whether
he was engaged in acting as a lookout or not” without Agent
Becka’s input. This argument fails to recognize the breadth
of the district court’s discretion in deciding whether to admit
or exclude evidence. Moreover, we have recognized in the
past that Agent Becka’s type of expertise can indeed assist
the trier of fact with its analysis of defendants’ conduct. See
Romero, 189 F.3d at 584; Sanchez-Galvez, 33 F.3d at 832.
Recognizing the value of such testimony, we have allowed
expert testimony describing how defendants’ otherwise
innocent-looking conduct was consistent with drug traffick-
ing counter-surveillance. See Sanchez-Galvez, 33 F.3d at
832; de Soto, 885 F.3d at 360. Agent Becka’s testimony
regarding Arturo’s activities during the July 10 transaction
was valuable notwithstanding the fact that the jury had
access to the surveillance tapes.
   Arturo also objects to the admission of Agent Becka’s
testimony on the ground that he took the stand both as an
eyewitness to Arturo’s conduct and as an expert regarding
narcotics counter-surveillance tactics. Agent Becka testified
that he witnessed Arturo “looking up and down the street
around and then looking back towards where I was told the
white Cadillac was parked.” He then explained to the jury
why, in his expert opinion, this seemingly innocuous
conduct indicated that Arturo was engaged in counter-sur-
veillance. While “[t]estifying as both eyewitness and expert
is permissible,” we recognize that “when these two roles are
Nos. 03-2056 & 03-2171                                        9

intertwined, the possibility of juror confusion is increased.”
de Soto, 885 F.3d at 360. This situation “place[s] an espe-
cially heavy burden on the district court to ensure that the
jury understood its function in evaluating the evidence.” Id.
This is particularly so where, as here, the activities sug-
gesting counter-surveillance may appear to be innocent. Id.
at 361.
  The district court was careful to avoid these pitfalls. First,
because it conducted an evidentiary hearing regarding
Agent Becka’s qualifications as an expert, Arturo knew
what to expect from him. Second, it gave the jury a caution-
ary instruction, in which it advised the jury to give Agent
Becka’s testimony “whatever weight you think it de-
serves”—that is to say, no special weight merely because
the agent was also testifying as an expert. Finally, both
counsel for Arturo and counsel for Correa engaged in rigor-
ous cross-examination of Agent Becka regarding his
expertise and the substance of his testimony.
   Arturo finally argues that, even if Agent Becka’s testimony
was reliable and relevant, the court should have excluded
it under FED. R. EVID. 403, which allows the court to exclude
relevant evidence “if its probative value is substantially
outweighed by the danger of unfair prejudice.” According to
Arturo, the real danger was either that the jury might have
attached undue weight to Agent Becka’s testimony or that
it might not have been able to disentangle his direct
observations from his expert knowledge. In United States v.
Mansoori, 304 F.3d 635 (7th Cir. 2002), we explained why
such dual testimony may be permitted, with the proper
safeguards:
    Although we have acknowledged that there is a greater
    danger of undue prejudice to the defendants when a
    witness testifies as both an expert and a fact witness,
    we have also indicated that a police officer may permis-
    sibly testify in both capacities. The potential for pre-
10                                  Nos. 03-2056 & 03-2171

     judice in this circumstance can be addressed by means
     of appropriate cautionary instructions and by examina-
     tion of the witness that is structured in such a way as
     to make clear when the witness is testifying to facts and
     when he is offering his opinion as an expert.
Id. at 654 (internal citations omitted). As we have already
noted, both of those measures were taken in this case, and
thus neither Rule 702 nor Rule 403 bars Agent Becka’s
testimony.
  We turn then to Arturo’s claim that there was insufficient
evidence to convict him of either the conspiracy offense or
the possession with intent to distribute offense. The task of
challenging the sufficiency of the evidence “is a daunting
one, as the standard of review that this court applies is
necessarily rigorous. Our threshold inquiry is whether ‘after
viewing the evidence in the light most favorable to the
prosecution, any rational trier of fact could have found the
essential elements of the crime beyond a reasonable doubt.’ ”
United States v. Curtis, 324 F.3d 501, 505 (7th Cir. 2003)
(quoting Jackson v. Virginia, 443 U.S. 307, 319 (1979)).
  We begin with Arturo’s conspiracy conviction. “A conspir-
acy conviction requires a showing that a conspiracy existed
(two or more persons joined together for the purpose of
committing a criminal act) and that the charged party knew
of and intended to join the agreement.” United States v.
Adkins, 274 F.3d 444, 450 (7th Cir. 2001) (internal quo-
tation marks omitted). “The government may establish these
elements through circumstantial evidence and the reason-
able inferences therein concerning the parties’ relationships,
their overt acts, and their overall conduct.” United States v.
Navarrete, 125 F.3d 559, 562 (7th Cir. 1997). Because
Arturo apparently concedes that a conspiracy existed, we
need determine only whether he knowingly and intention-
ally joined that conspiracy. Arturo contends that there is
insufficient evidence to establish his involvement, citing the
Nos. 03-2056 & 03-2171                                     11

absence of drugs or drug paraphernalia in his bedroom at
1503 Porter Avenue, the lack of any cellular phone records
or drug ledgers linking him to the conspiracy, and his
nonparticipation in the undercover transactions prior to
July 10. The government counters by detailing Arturo’s role
in retrieving the kilogram of cocaine from Chicago on July
10 and Agent Becka’s testimony that Arturo’s conduct at
the scene of the July 10 transaction was consistent with
drug trafficking counter-surveillance. In addition, the gov-
ernment points to Varela’s testimony that Arturo explained
that he was present at the July 10 transaction because his
brother thought Varela was going to steal the money.
   “Although mere presence is insufficient to show that the
defendant was acting in furtherance of a conspiracy, the
government can prove that a defendant joined a conspiracy
if his presence, along with other evidence indicating that
the presence or act was intended to advance the ends of the
conspiracy is shown.” Navarrete, 125 F.3d at 562 (internal
quotation marks omitted). Our analysis in United States v.
Sasson, 62 F.3d 874 (7th Cir. 1995), is instructive. There we
found sufficient evidence to support the jury’s conclusion
that defendant Sasson knowingly and intentionally joined
a drug distribution conspiracy by providing counter-surveil-
lance. Id. at 888. Like Arturo, Sasson did not personally
conduct the drug transactions, but the remainder of his
behavior indicated that he was acting as a lookout. In
finding the evidence sufficient to prove Sasson’s involvement
in the conspiracy, we explained:
    Whether a defendant’s behavior constitutes counter-
    surveillance or simply loitering is a question of fact for
    the jury to decide, and the fact that Sasson did not have
    all the usual “trappings” of a drug dealer is not dispos-
    itive. . . . Under the circumstances and given the fact
    that Sasson accompanied [the dealer] to each and every
    one of the five drug transactions, a reasonable juror
    could very easily conclude that Sasson was there to serve
    as a “lookout” and to see that the drug deals were suc-
12                                   Nos. 03-2056 & 03-2171

     cessfully completed, justifying the logical inference that
     Sasson was an active participant in the conspiracy.
 Id. at 887 (internal citations and quotation marks
omitted).
  We have repeatedly stated that “engaging solely in coun-
ter-surveillance at a drug transaction is sufficient to prove
participation or membership in a conspiracy to sell drugs.”
Id.; see also United States v. Saadeh, 61 F.3d 510, 525 (7th
Cir. 1995); Sanchez-Galvez, 33 F.3d at 834; United States v.
Brigham, 977 F.2d 317, 319 (7th Cir. 1992). Viewing the
evidence in the light most favorable to the prosecution, as
we must, we hold that a reasonable jury could have credited
Agent Becka’s testimony and found that Arturo engaged in
counter-surveillance on July 10. See Navarrete, 125 F.3d at
562-63. As “counter-surveillance at a drug transaction is
sufficient to prove participation or membership in a con-
spiracy to sell drugs,” Sasson, 62 F.3d at 887, Arturo cannot
prevail on his insufficiency of the evidence claim with
respect to his conspiracy conviction.
  We likewise hold that there was sufficient evidence to
support Arturo’s conviction for knowingly possessing with
intent to distribute cocaine. To prove this charge, “the
Government had to show three things: 1) knowing or inten-
tional possession of the drug, 2) possession with intent to
distribute and 3) knowledge that the drug was a controlled
substance.” United States v. Harris, 325 F.3d 865, 868 (7th
Cir. 2003). Arturo argues that there was insufficient evi-
dence to convict him, relying primarily on the lack of direct
evidence that he ever possessed the kilogram of cocaine
which was the subject of the July 10, 2002, transaction.
  The absence of direct evidence in no way demonstrates
that there was insufficient evidence of Arturo’s possession
of cocaine. As we have often stated, “[i]n addition to actual
possession, possession can be constructive, and constructive
possession can be established through circumstantial
Nos. 03-2056 & 03-2171                                     13

evidence. Constructive possession exists where the evidence
demonstrates ownership, dominion, authority, or control.
Constructive possession may be sole or joint.” United States
v. Richardson, 208 F.3d 626, 632 (7th Cir. 2000) (internal
citations omitted). To show constructive possession, “the
government [must] establish a nexus between the accused
and the contraband, in order to distinguish the accused
from a mere bystander.” Id.
  On several occasions, we have found possession with in-
tent to distribute a controlled substance when the defendant
denied knowledge of drugs that were located in the car that
she was driving or in which she was a passenger. See
United States v. Griffin, 150 F.3d 778 (7th Cir. 1998);
United States v. Elizondo, 920 F.2d 1308 (7th Cir. 1990).
This case is the same. Arturo and Luis left their home for
Chicago minutes after Varela called his source; they spent
only 19 minutes in Chicago; they opened the trunk of the
car while in Chicago and again upon arriving in Janesville,
which was not their city of departure; they drove the car to
several locations and walked around and near the car sus-
piciously; and when they arrived at the Quick Stop, Arturo
positioned himself on a corner where he could monitor the
car and repeatedly looked around and at the car. Ultimately,
the agents seized a kilogram of cocaine from the trunk of
the car. A reasonable jury was entitled to conclude that
Arturo had constructive joint possession of the cocaine in the
trunk of the car, arising from his “shared rights of dominion
and control” over the drugs, even if he never admitted that
he knew about the cocaine in the vehicle.
  Finally, we turn to Arturo’s argument that the district
court erred in refusing to reduce his offense level based on
an alleged minor role in the conspiracy. Before discussing
this issue, however, we must place Arturo’s appeal in con-
text for purposes of United States v. Booker, supra, 125 S.Ct.
738. Neither before the district court nor before this court
has Arturo raised any argument to the effect that the dis-
14                                  Nos. 03-2056 & 03-2171

trict court’s use of the Sentencing Guidelines violated the
Constitution, the rule announced in Apprendi v. New Jersey,
530 U.S. 466 (2000), Blakely, or Booker. Nonetheless, it is
still within this court’s discretion to recognize plain error
where it occurs. See FED. R. CRIM. P. 52(b) (“A plain error
that affects substantial rights may be considered even though
it was not brought to the court’s attention.”). For the rea-
sons we explained in Paladino, supra, 2005 WL 435430, at
*9, Arturo’s sentence may be tainted with plain error. For
the benefit of the district court on the limited remand we
are ordering, however, we address Arturo’s Guidelines-
based argument that he should have received the minor role
adjustment. This is appropriate because the Guidelines
continue to have force as advisory statements even after the
Supreme Court’s Booker decision, and thus there is still a
strong interest in ensuring that they are applied properly.
  Section 3B1.2 of the U.S. Sentencing Guidelines provides:
     Based on the defendant’s role in the offense, decrease
     the offense level as follows:
     (a) If the defendant was a minimal participant in any
         criminal activity, decrease by 4 levels.
     (b) If the defendant was a minor participant in any
         criminal activity, decrease by 2 levels.
     In cases falling between (a) and (b), decrease by 3
     levels.
Application Note 5 defines a minor participant as one “who
is less culpable than most other participants, but whose role
could not be described as minimal.” Before Booker, we
reviewed the district court’s decision to deny a defendant a
downward adjustment for a lesser role in criminal activity
under § 3B1.2 for clear error. United States v. Hanhardt, 361
F.3d 382, 394 (7th Cir. 2004), vacated and remanded for
further proceedings sub nom. Altobello v. United States, 125
S. Ct. 994 (2005). We shall do the same here.
Nos. 03-2056 & 03-2171                                      15

  Arturo argues that he “certainly wasn’t involved in the
conspiracy prior to the day it all ended, July 10, 2002,” and
that the court therefore wrongly held him “accountable for
an amount in excess of what his involvement and the record
substantiates.” In response, the government points to
Arturo’s involvement in transporting the drugs to Janesville
from Chicago and acting as a lookout during the sale, as
well as Varela’s statements to the officers that he made a
payment of a drug debt to Arturo and purchased an ounce
of cocaine from him prior to the July 10 delivery. Arturo
dismisses Varela’s testimony as “simply incredible,” but the
district court found otherwise, stating: “I’m not persuaded
that Mr. Varela lied about everything that he testified to at
trial. I think that a certain amount of his testimony was
quite believable.” The court concluded that Arturo did not
merit a minor role reduction because he joined the conspir-
acy prior to July 10, 2002, as evidenced by his introducing
Varela to Luis, delivering cocaine to Varela on behalf of
Luis, and accepting drug payments from Varela.
  The record before us does not convince us that the district
court erred in its evaluation of Arturo’s role in the offense.
The court’s reliance on Arturo’s participation in transport-
ing the cocaine and providing counter-surveillance and
Varela’s testimony regarding Arturo’s involvement in the
conspiracy prior to the July 10 sale, which it credited, pro-
vided adequate support for its decision. See United States
v. Galbraith, 200 F.3d 1006, 1012 (7th Cir. 2000). We have
held that “[w]hen it appears that although one person was
the ‘driving force’ in a criminal scheme, yet the defendant
still had ‘an integral role assisting him’ in the enterprise,
the defendant will not receive a reduction in his offense level
pursuant to U.S.S.G. § 3B1.2(a).” United States v. Navarro,
90 F.3d 1245, 1263 (7th Cir. 1996). The district court rea-
sonably could have concluded that Arturo played such an
integral role, even though Luis may have orchestrated the
cocaine distribution conspiracy. The court did not clearly err
in refusing to grant Arturo a minor role adjustment.
16                                  Nos. 03-2056 & 03-2171

                  B. Magdalena Correa
  Initially, Correa’s sole argument on appeal was that law
enforcement officials lacked probable cause to arrest her
during the July 10 transaction, and hence that the district
court erred in denying her motion to suppress the evidence
obtained in the search of her vehicle incident to that arrest.
After oral argument, we gave her permission to file a
supplemental brief arguing that her Sixth Amendment
right to a jury trial was violated when the district court
based her sentence on facts not found by the jury, including
the amount of cocaine for which she was responsible, her
obstruction of justice, the use of a weapon, and her role as
a leader. Correa conceded in her supplemental brief that
she had not raised this issue before the district court. We
consider first her arguments with respect to her arrest and
the suppression of the evidence, and then her sentencing
arguments.
   “In order to have probable cause for an arrest, law en-
forcement agents must reasonably believe, in light of the
facts and circumstances within their knowledge at the time
of the arrest, that the suspect had committed or was com-
mitting an offense.” Payne v. Pauley, 337 F.3d 767, 776 (7th
Cir. 2003). The fact-intensive, on-the-spot determination of
probable cause often involves an exercise of judgment, which
“ ‘turn[s] on the assessment of probabilities in particular
factual contexts—not readily, or even usefully, reduced to
a neat set of legal rules.’ ” Maxwell v. City of Indianapolis,
998 F.2d 431, 434 (7th Cir. 1993) (quoting Ill. v. Gates, 462
U.S. 213, 232 (1983)). Therefore, courts evaluate probable
cause “not on the facts as an omniscient observer would per-
ceive them but on the facts as they would have appeared to
a reasonable person in the position of the arresting officer—
seeing what he saw, hearing what he heard.” Mahoney v.
Kesery, 976 F.2d 1054, 1057 (7th Cir. 1992). “So long as the
totality of the circumstances, viewed in a common sense
manner, reveals a probability or substantial chance of crim-
Nos. 03-2056 & 03-2171                                      17

inal activity on the suspect’s part, probable cause exists.”
United States v. Sawyer, 224 F.3d 675, 679 (7th Cir. 2000).
  We review de novo the court’s ultimate conclusion whether
the law enforcement officers had probable cause. Id. at 679.
Nonetheless, findings of historical fact are reviewed only for
clear error. Ornelas v. United States, 517 U.S. 690, 699
(1996). In reviewing a denial of a suppression motion, we
may consider evidence introduced both at the suppression
hearing and at trial. United States v. Yang, 286 F.3d 940,
948 n.4 (7th Cir. 2002); United States v. Duguay, 93 F.3d 346,
350 (7th Cir. 1996); United States v. Trevino, 60 F.3d 333,
336 (7th Cir. 1995).
  The government contends that this case is governed by
the “collective knowledge doctrine,” under which “[t]he police
who actually make the arrest need not personally know all
the facts that constitute probable cause if they reasonably
are acting at the direction of another officer or police agency.
In that case, the arrest is proper so long as the knowledge
of the officer directing the arrest, or the collective knowledge
of the agency he works for, is sufficient to constitute prob-
able cause.” Tangwall v. Stuckey, 135 F.3d 510, 517 (7th Cir.
1998) (emphasis removed); see also United States v. Lenoir,
318 F.3d 725, 728 (7th Cir. 2003). This doctrine is rooted in
the Supreme Court’s holding in United States v. Hensley,
469 U.S. 221 (1985), 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, cannot be expected to
cross-examine their fellow officers about the foundation for
the transmitted information.” Id. at 231 (internal quotation
marks omitted). Courts have applied the collective knowl-
edge doctrine in two situations: first, when information from
one jurisdiction is actually relayed to officers or agencies in
another jurisdiction to permit coordination of investigations
and the speedy apprehension of fleeing suspects, see United
States v. Nafzger, 974 F.2d 906, 910 (7th Cir. 1992), and
18                                  Nos. 03-2056 & 03-2171

second, “when officers are in communication with each
other while working together at a scene.” Id. at 911; see also
Sawyer, 224 F.3d at 680. In the latter group of cases, the
knowledge of the officers may be imputed to one another
“even when there is no express testimony that the specific
or detailed information creating the justification for a stop
was conveyed (though of course the information actually
possessed by the officers must be sufficient to justify the
stop or arrest).” 974 F.2d at 911.
  To apply the collective knowledge doctrine here, we must
determine first what knowledge can be imputed to the
officers at the time that they arrested Correa, and second
whether that knowledge was sufficient for the officers to
form a reasonable belief that she was engaged in criminal
activity. When Correa was arrested, the team of officers at
the scene had the following information regarding her in-
volvement in the drug transaction: (1) on July 10, 2002, she
departed from 1503 Porter Avenue, the residence that she
shared with Arturo and Luis; (2) she drove the same brown
Cadillac (with the same license plate) as that parked in front
of Varela’s house during the June 25, 2002 drug transaction;
(3) when the brown Cadillac returned to Varela’s house after
the delivery of the cocaine to the undercover agents, an
Hispanic woman was in the passenger seat; (4) on July 10,
agents followed Correa from 1503 Porter Avenue to the Quick
Mart, where she spoke briefly to Luis; (5) she then spoke
briefly with Varela in the Mexican supermarket’s parking
lot, immediately prior to his leading Luna to the trunk of
the white Cadillac; and (6) after this exchange and before
Varela revealed the cocaine, she parked the brown Cadillac
where it would be possible for her to monitor the trunk of
the white Cadillac through her rearview mirror.
  We find this evidence sufficient for an officer to have
formed “a reasonable belief to suspect criminal activity” on
the part of Correa. In these situations, “law enforcement
Nos. 03-2056 & 03-2171                                     19

agents are entitled to draw reasonable inferences from the
facts before them, based on their training and expertise.”
United States v. Funches, 327 F.3d 582, 586 (7th Cir. 2003).
As in Funches, the agents here had extensive experience in
narcotics enforcement, which is relevant to an informed
assessment of the facts. See generally 2 WAYNE R. LAFAVE,
SEARCH AND SEIZURE § 3.2(c), at 38 (3d ed. 1996).
   Agent Becka and Agent Hehr testified that they each
have 19 years of experience as DEA agents, with the latter
serving as the resident agent in charge of the DEA office in
Madison, Wisconsin. Trained narcotics officers like these two,
who observed Correa’s activities in this case, could rea-
sonably conclude that she was engaged in counter-surveil-
lance during the July 10 transaction, based on the facts we
have just reviewed. See United States v. Carpenter, 342 F.3d
812, 815 (7th Cir. 2003); see also United States v. Ocampo,
937 F.2d 485, 490 (9th Cir. 1991). We therefore find that
the totality of the circumstances, when considered in light
of the DEA agents’ training and experience, gave them suf-
ficient reason to believe that there was a significant prob-
ability that Correa was committing a crime. See United States
v. Carrillo, 269 F.3d 761, 767 (7th Cir. 2001).
  Having found sufficient evidence in the aggregate to
establish probable cause for Correa’s arrest, we must de-
termine whether this information can be imputed to the
officers who arrested her. Although we do not know who
issued the order for Correa’s arrest and the precise infor-
mation in the minds of the officers who carried it out, the
record shows that the officers conducting surveillance during
the July 10 transaction were in close communication with
each other. Agent Becka, who also provided surveillance
during the June 25 undercover transaction at which the
brown Cadillac was observed, testified that during the July
10 transaction he shared a surveillance van with Agent
Jeanne Hehr, who arrested Correa, and two other officers.
Agent Hehr testified that she received “numerous cellular
20                                   Nos. 03-2056 & 03-2171

phone calls throughout the transaction” from other officers,
reporting the activities and locations of the parties and the
arrest of Varela and Luis. In addition, Agent Becka con-
firmed that Agent Chamulak, who was at the scene of the
July 10 transaction in an undercover capacity, radioed to
Agents Becka and Hehr that Correa had repositioned her
car so as to monitor the white Cadillac. Finally, Special Agent
Edward Wall of the Division of Narcotics Enforcement for
the Wisconsin Department of Justice, who conducted aerial
surveillance of the trip to Chicago and the subsequent
transaction in Janesville, including the movements of the
brown Cadillac, testified that he was in communication with
the surveillance team on the ground via radio.
   This team of officers therefore worked together closely in
monitoring the drug transaction as it unfolded. In such a
case, we have found that the officers’ “knowledge may be
mutually imputed even when there is no express testimony
that the specific or detailed information creating the justi-
fication for a stop was conveyed.” Nafzger, 974 F.2d at 911;
see also United States v. Edwards, 885 F.2d 377, 383 (7th
Cir. 1989); Sawyer, 224 F.3d at 680. In particular, the team
of officers monitoring the July 10 transaction were in close
contact throughout. Agent Hehr, who arrested Correa, was
in constant communication with Agent Becka and Agent
Chamulak. On this basis, we find the collective knowledge
doctrine applicable, and given that the information avail-
able to the officers at the time of Correa’s arrest provided
probable cause, we affirm the district court’s denial of her
motion to suppress.
  We now turn to Correa’s challenge to her sentence. In
keeping with our decision in Paladino, 2005 WL 435430, we
review Correa’s arguments under Blakely/Booker for plain
error. Because there is nothing out of the ordinary about
her case, compare United States v. Lee, 399 F.3d 864 (7th
Cir. 2005), we conclude that Correa is also entitled to a
limited remand to ascertain whether the district court
Nos. 03-2056 & 03-2171                                      21

would have imposed the same sentence had it realized that
the Guidelines were advisory only.
   Correa’s sentence depended in large part on the district
court’s application of the Guidelines. As she points out, the
indictment in her case charged her with offenses involving
“more than” 500 grams of a substance containing cocaine.
It did not charge that she played a leadership role in the
conspiracy, that she possessed a dangerous weapon, or that
she obstructed justice. The jury therefore never made any
of the latter three findings, nor can one say whether it
found any more than a smidgeon over 500 grams of the
controlled substance. The district court, proceeding natur-
ally enough under the Guidelines, found that Correa should
be responsible for 1.56 kilograms of cocaine. See U.S.S.G.
§ 1B1.3. It also found that she possessed a dangerous weapon
in connection with the offense and raised her Guidelines
offense level by two on that basis, see U.S.S.G. § 2D1.1(b)(1);
it found that she played a leadership role and accordingly
raised her offense level by another two, see U.S.S.G.
§ 3B1.1(c); and it found that she had obstructed justice and
thereby earned a final two-level increase under U.S.S.G.
§ 3C1.1. These adjustments for relevant conduct and other
factors resulted in an increase in her offense level from a 26
to a 32, and changed the sentencing range from 63 to 78
months up to 121 to 151 months. The district court sentenced
her at the bottom of the adjusted range, to 121 months.
  Particularly in this kind of case, we do not know if the
judge, sentencing with the new flexibility afforded by Booker,
would have concluded that 121 months was a “reasonable”
sentence. In order to guide the court’s deliberations on the
limited remand, however, we comment briefly on the points
related to the application of the Guidelines that Correa has
already raised.
  Relevant Conduct. The jury found that Correa was
responsible for more than 500 grams of cocaine, while the
22                                  Nos. 03-2056 & 03-2171

court concluded that the exact amount for which she should
be held responsible was 1.56 kilograms. Because that
amount was less than two kilograms, it did not increase the
offense level that followed from the jury’s verdict. See
U.S.S.G. § 2D1.1(c)(7).
  Weapon. The court found that Correa had two weapons,
and that it was not “clearly improbable that the weapon(s)
[were] connected with the offense.” See U.S.S.G. § 2D1.1(b)(1)
and Application Note 3. One was a gun found under the
mattress in her bedroom, and the other was a gun she kept
in her purse. The court noted that she was selling drugs out
of the house, and thus that it could not say that the guns
had no connection with the offense. It also found that she
had displayed a firearm to co-conspirator Varela to in-
timidate him. We see no clear error in these factual findings,
whatever their relevance may be to the ultimate reasonable
sentence.
  Role in the Offense. Initially, the government urged that
Correa receive a four-level upward adjustment in her sen-
tencing level for a leadership role in the conspiracy, pursu-
ant to U.S.S.G. § 3B1.1(a). In the end, however, the court
imposed only a two-level upward adjustment under § 3B1.1(c),
which is available for someone who is an “organizer, leader,
manager or supervisor” in a capacity other than those cov-
ered by the higher enhancements. The court was concerned
that the government had not adequately shown that the ac-
tivity involved five or more participants, which is required
for the four-level enhancement. On this point, the court
gave Correa the benefit of the doubt. It found that she was
at least a manager or supervisor of the group’s activities,
along with Luis. That finding is supported in the record,
should the judge consider it appropriate once again to take
this factor into account.
  Obstruction of Justice. This enhancement under U.S.S.G.
§ 3C1.1 is perhaps the easiest to support in the record. The
Nos. 03-2056 & 03-2171                                     23

district court found that Correa had lied at the trial when
she testified that she had no knowledge of the drug traf-
ficking conspiracy. The jury’s verdict, among other things,
squarely contradicts her assertion. (The jury did not find the
other elements of an obstruction offense, and so we assume
that its apparent conclusion that Correa was untruthful is
not the end of this argument.) The court also found that she
lied when she said that the drug ledger did not belong to
her, but instead was Luis’s exclusive property, and when she
claimed that she was not acting as a lookout for the sale.
Again, the jury’s findings strongly contradict these asser-
tions. Defendants who obstruct justice are particularly
culpable, as both common sense and the Guidelines recog-
nize. This factor may also play a part in the offense level
computed for purposes of an advisory use of the Guidelines.


                             III
  For these reasons, we AFFIRM the district court’s denial of
Correa’s motion to suppress and the judgment of guilt with
respect to Arturo Garcia Parra. We order a LIMITED RE-
MAND with respect to both sentences, while retaining
jurisdiction, in accordance with the procedure set forth in
Paladino.

A true Copy:
       Teste:

                        ________________________________
                        Clerk of the United States Court of
                          Appeals for the Seventh Circuit




                   USCA-02-C-0072—3-29-05
