                           PUBLISHED

UNITED STATES COURT OF APPEALS
                 FOR THE FOURTH CIRCUIT


UNITED STATES OF AMERICA,               
                 Plaintiff-Appellant,
                 v.                             No. 02-4953
WILLIAM ADDERSON JARRETT,
              Defendant-Appellee.
                                        
           Appeal from the United States District Court
         for the Eastern District of Virginia, at Richmond.
            Richard L. Williams, Senior District Judge.
                            (CR-02-11)

                       Argued: June 3, 2003

                       Decided: July 29, 2003

      Before WILKINSON and MOTZ, Circuit Judges, and
   Robert R. BEEZER, Senior Circuit Judge of the United States
   Court of Appeals for the Ninth Circuit, sitting by designation.



Reversed and remanded by published opinion. Judge Motz wrote the
opinion, in which Judge Wilkinson and Senior Judge Beezer joined.


                             COUNSEL

ARGUED: Michael James Elston, Assistant United States Attorney,
Alexandria, Virginia, for Appellant. Jeffrey Lee Everhart, RICE,
EVERHART & BABER, Richmond, Virginia, for Appellee. ON
BRIEF: Paul J. McNulty, United States Attorney, Brian R. Hood,
Assistant United States Attorney, Alexandria, Virginia, for Appellant.
2                      UNITED STATES v. JARRETT
                               OPINION

DIANA GRIBBON MOTZ, Circuit Judge:

   In this case, the Government used information provided by an
anonymous computer hacker to initiate a search which produced evi-
dence that William Jarrett violated federal statutes prohibiting the
manufacture and receipt of child pornography. The district court sup-
pressed this evidence on the ground that the hacker acted as a Govern-
ment agent, and so violated the Fourth Amendment, when he
procured pornographic files from Jarrett’s computer. The Government
appeals. Because the Government did not know of, or in any way par-
ticipate in, the hacker’s search of Jarrett’s computer at the time of that
search, the hacker did not act as a Government agent. Accordingly,
we reverse and remand for further proceedings.

                                    I.

   The parties do not dispute the underlying facts. Prior to his involve-
ment in the case at hand, the hacker, referred to as Unknownuser, pro-
vided information through emails during July 2000 to the FBI and law
enforcement agents in Alabama regarding a child pornographer, Dr.
Bradley Steiger. In an early email, Unknownuser identified himself
only as someone "from Istanbul, Turkey," who could not "afford an
overseas phone call and cannot speak English fluently."

   Employing the same method that he would later use to hack into
Jarrett’s computer, Unknownuser obtained access to Steiger’s com-
puter via a so-called Trojan Horse program that Unknownuser had
attached to a picture he posted to a news group frequented by pornog-
raphy enthusiasts. When Steiger downloaded the picture to his own
computer, he inadvertently downloaded the Trojan Horse program,
which then permitted Unknownuser to enter Steiger’s computer unde-
tected via the Internet. See United States v. Steiger, 318 F.3d 1039,
1044 (11th Cir. 2003). After searching Steiger’s hard drive and find-
ing evidence of child pornography, Unknownuser copied certain files
and then emailed the information to the law enforcement officials
who used it to identify and apprehend Steiger. A jury convicted
Steiger of violating various federal statutes prohibiting the sexual
                       UNITED STATES v. JARRETT                        3
exploitation of minors. He was sentenced to 210 months in prison. Id.
at 1045.1

   Shortly after Steiger was indicted, in late November 2000, FBI
Special Agent James Duffy, who served as Legal Attache for the FBI
in Turkey, contacted Unknownuser via email and phone. In addition
to informing Unknownuser that he would not be prosecuted for his
assistance in apprehending Steiger, Duffy requested a meeting and
posed a series of questions to Unknownuser, with the hope that
Unknownuser would reveal his identity and perhaps agree to testify
at Steiger’s trial. Although Unknownuser was quite forthcoming in
his responses, he refused to meet with Agent Duffy, stating emphati-
cally that he would never allow himself to be identified. Agent Duffy
closed this exchange (in an email dated December 4, 2000) by thank-
ing Unknownuser for his assistance and stating that "If you want to
bring other information forward, I am available."

   Five months later, Agent Duffy contacted Unknownuser via email,
informing him of a postponement in the Steiger trial, thanking him
again for his assistance, and assuring him that he would not be prose-
cuted for his actions should he decide to serve as a witness in the
Steiger trial. Unknownuser responded, repeating that he had no inten-
tion of revealing his identity.

   The next contact between Unknownuser and law enforcement did
not occur until December 3, 2001, almost seven months later, when
Unknownuser sent an unsolicited email to his contact at the Mont-
gomery, Alabama Police Department, Kevin Murphy, informing Mur-
phy that he had "found another child molester . . . from Richmond,
VA" and requesting contact information for someone at the FBI deal-
ing with these sorts of crimes. The alleged child molester referred to
in the email was William Jarrett.
  1
   Steiger appealed his conviction on the ground that the evidence
obtained from Unknownuser, which provided a partial basis for the
search warrant, should have been suppressed because Unknownuser
acted as an agent of the Government when he hacked into Steiger’s com-
puter. The Eleventh Circuit rejected this argument, reasoning that
Unknownuser acquired all of the relevant information about Steiger
before he contacted law enforcement, and thus was, at all material times,
acting as a private individual. Steiger, 318 F.3d at 1045-46.
4                      UNITED STATES v. JARRETT
   After contacting the FBI, Murphy informed Unknownuser that the
FBI preferred that Unknownuser send the new information to Mur-
phy’s email address. On December 4, 2001, Unknownuser sent thir-
teen email messages to Murphy, including a ten-part series of emails
with some forty-five attached files containing the "evidence" that
Unknownuser had collected on Jarrett. Murphy forwarded the infor-
mation to agents at the FBI, who initiated an investigation.

   Based on the information provided by Unknownuser, the Govern-
ment filed a criminal complaint and application for a search warrant
against Jarrett on December 13, 2001. After receiving authorization
from the district court, the FBI promptly executed the search warrant
and arrested Jarrett.2

   Several days after Jarrett’s arrest, on December 16, 2001, Agent
Duffy sent Unknownuser an email informing him of Steiger’s sen-
tence and thanking Unknownuser for his assistance in the case. At the
time, Duffy was unaware of the Jarrett investigation. The next day,
Unknownuser replied, informing Duffy of his efforts to identify Jar-
rett and inquiring why he had heard nothing since he sent the Jarrett
files to Murphy on December 4. Unknownuser sent a similar message
the following day (December 18) indicating that he had read about
Jarrett’s arrest in the newspaper and asking Agent Duffy to have
Agent Margaret Faulkner — a special agent based in Alabama who
had been involved in the Steiger investigation — contact him. On
December 19, 2001, Agent Duffy sent an email to Unknownuser
thanking him again for his assistance, providing information on the
Jarrett investigation and prosecution, and requesting that
Unknownuser maintain email contact with Agent Faulkner via her
personal email address.
    2
   The district court noted that authorities arrested Jarrett on the thir-
teenth or the fourteenth of December. At the hearing on Jarrett’s suppres-
sion motion, the court explained that "[t]he affidavit that supplied the
probable cause for the search warrant was based on files obtained from
the defendant’s computer by an anonymous hacker using an email
address of ‘unknown user.’ By illegally hacking onto the defendant’s
computer through the internet, the ‘unknown user’ searched the defen-
dant’s computer files, copied information, and forwarded the information
to the government."
                      UNITED STATES v. JARRETT                       5
   Three weeks later, on January 9, 2002, a grand jury indicted Jarrett
on one count of manufacturing child pornography in violation of 18
U.S.C.A. § 2251(a) (West 2000) and seven counts of receiving child
pornography in violation of 18 U.S.C.A. § 2252A(a)(2)(A) (West
2000). Jarrett moved to suppress the evidence obtained through the
execution of the search warrant on the ground that the Government
violated his Fourth Amendment rights in using the information pro-
vided by Unknownuser to secure the search warrant. The district court
denied the motion. Jarrett then entered a conditional guilty plea to a
one-count criminal information charging him with manufacturing
child pornography.

   Prior to sentencing, however, Jarrett moved to reconsider his ear-
lier motion to suppress on the basis of new evidence — a series of
emails exchanged between Unknownuser and FBI agent Faulkner,
beginning shortly after Jarrett’s arrest and extending for almost two
months. The Government did not disclose these emails until after Jar-
rett had entered his guilty plea.

   In the initial email in this series, dated December 19, 2001, Agent
Faulkner explicitly thanked Unknownuser for providing the informa-
tion to law enforcement officials. She then engaged in what can only
be characterized as the proverbial "wink and a nod":

    I can not ask you to search out cases such as the ones you
    have sent to us. That would make you an agent of the Fed-
    eral Government and make how you obtain your informa-
    tion illegal and we could not use it against the men in the
    pictures you send. But if you should happen across such pic-
    tures as the ones you have sent to us and wish us to look into
    the matter, please feel free to send them to us. We may have
    lots of questions and have to email you with the questions.
    But as long as you are not ‘hacking’ at our request, we can
    take the pictures and identify the men and take them to
    court. We also have no desire to charge you with hacking.
    You are not a US citizen and are not bound by our laws.

Over the course of the next two months, Agent Faulkner sent at least
four additional email messages, which constituted, in the words of the
district court, a "‘pen-pal’ type correspondence" with Unknownuser.
6                     UNITED STATES v. JARRETT
In addition to expressing gratitude and admiration for Unknownuser,
Faulkner repeatedly sought to reassure Unknownuser that he was not
a target of law enforcement for his hacking activities. For example,
in an email dated January 29, 2002, she stated that

    the FACT still stands that you are not a citizen of the United
    States and are not bound by our laws. Our Federal attorneys
    have expressed NO desire to charge you with any CRIMI-
    NAL offense. You have not hacked into any computer at the
    request of the FBI or other law enfor[ce]ment agency. You
    have not acted as an agent for the FBI or other law enforce-
    ment agency. Therefore, the information you have collected
    can be used in our criminal trials.

In his responses to Agent Faulkner, Unknownuser spoke freely of his
"hacking adventures" and suggested in no uncertain terms that he
would continue to search for child pornographers using the same
methods employed to identify Steiger and Jarrett. As found by the dis-
trict court, Agent Faulkner, despite her knowledge of Unknownuser’s
illegal hacking, "never instruct[ed] Unknownuser that he should cease
hacking."

   Upon consideration of this series of emails, the district court
reversed its earlier decision and suppressed the evidence obtained
during the search of Jarrett’s residence. At the same time, the court
deemed Jarrett’s motion to reconsider as a motion to withdraw his
guilty plea, which it promptly granted. The court reasoned that the
"totality of all the contact between law enforcement and
Unknownuser encourage[d] Unknownuser to continue his behavior
and to remain in contact with the FBI." The district court thus con-
cluded that the Government and Unknownuser had "expressed their
consent to an agency relationship," thereby rendering any evidence
obtained on the basis of Unknownuser’s hacking activities inadmissi-
ble on the ground that it was procured in violation of Jarrett’s Fourth
Amendment rights.

                                  II.

  In considering the Government’s appeal of the district court’s sup-
pression ruling, we have jurisdiction pursuant to 18 U.S.C.A. § 3731
                       UNITED STATES v. JARRETT                         7
(West Supp. 2003). We review the district court’s factual findings for
clear error and its legal determinations de novo. United States v. Elly-
son, 326 F.3d 522, 527 (4th Cir. 2003) (citing Ornelas v. United
States, 517 U.S. 690, 699 (1996)).

   The Fourth Amendment protects against unreasonable searches and
seizures by Government officials and those private individuals acting
as "instrument[s] or agent[s]" of the Government. See U.S. Const.
amend. IV; Coolidge v. New Hampshire, 403 U.S. 443, 487 (1971).
It does not provide protection against searches by private individuals
acting in a private capacity. See United States v. Jacobsen, 466 U.S.
109, 113 (1984) (holding that the Fourth Amendment is "wholly inap-
plicable to a search or seizure, even an unreasonable one, effected by
a private individual not acting as an agent of the Government or with
the participation or knowledge of any governmental official" (internal
quotation marks and citation omitted)). Thus, "‘evidence secured by
private searches, even if illegal, need not be excluded from a criminal
trial.’" Ellyson, 326 F.3d at 527 (quoting United States v. Kinney, 953
F.2d 863, 865 (4th Cir. 1992)); see also United States v. Walter, 447
U.S. 649, 656 (1980) ("[A] wrongful search or seizure conducted by
a private party does not violate the Fourth Amendment and . . . such
private wrongdoing does not deprive the government of the right to
use evidence that it has acquired lawfully." (citing Coolidge, 403 U.S.
at 487-90)).

   Determining whether the requisite agency relationship exists "nec-
essarily turns on the degree of the Government’s participation in the
private party’s activities, . . . a question that can only be resolved ‘in
light of all the circumstances.’" Skinner v. Railway Labor Executives’
Ass’n, 489 U.S. 602, 614-15 (1989) (quoting Coolidge, 403 U.S. at
487). This is a "a fact-intensive inquiry that is guided by common law
agency principles." Ellyson, 326 F.3d at 527 (citation omitted). The
defendant bears the burden of proving that an agency relationship
exists. Id. (citation omitted).

   In order to run afoul of the Fourth Amendment, therefore, the Gov-
ernment must do more than passively accept or acquiesce in a private
party’s search efforts. Rather, there must be some degree of Govern-
ment participation in the private search. In Skinner, for example, the
Supreme Court found that private railroads, in performing drug tests
8                     UNITED STATES v. JARRETT
on their employees in a manner expressly encouraged and authorized
under Government regulations, acted as Government agents sufficient
to implicate the Fourth Amendment. Skinner, 489 U.S. at 615-16. As
the Court concluded, "specific features of the regulations combine to
convince us that the Government did more than adopt a passive posi-
tion toward the underlying private conduct." Id., 489 U.S. at 615
(emphasis added).

   Following the Supreme Court’s pronouncements on the matter, the
Courts of Appeals have identified two primary factors that should be
considered in determining whether a search conducted by a private
person constitutes a Government search triggering Fourth Amend-
ment protections. These are: (1) whether the Government knew of and
acquiesced in the private search; and (2) whether the private individ-
ual intended to assist law enforcement or had some other independent
motivation. See, e.g., United States v. Paige, 136 F.3d 1012, 1017-18
(5th Cir. 1998); United States v. Feffer, 831 F.2d 734, 739 (7th Cir.
1987); United States v. Walther, 652 F.2d 788, 791-92 (9th Cir.
1981). Although we have never articulated a specific "test," we too
have embraced this two-factor approach, which we have compressed
into "[o]ne highly pertinent consideration." See Ellyson, 326 F.3d at
527 ("One highly pertinent consideration is ‘whether the government
knew of and acquiesced in the intrusive conduct and whether the pri-
vate party’s purpose for conducting the search was to assist law
enforcement efforts or to further her own ends.’" (quoting Feffer, 831
F.2d at 739)).

   In this case, the Government concedes the existence of the second
factor — that Unknownuser’s motivation for conducting the illicit
searches stemmed solely from his interest in assisting law enforce-
ment authorities. Thus, the only question before us concerns the first
factor — did the Government know of and acquiesce in
Unknownuser’s search in a manner sufficient to transform
Unknownuser into an agent of the Government, and so render the
search unconstitutional.

   In seeking to give content to this factor, we have required evidence
of more than mere knowledge and passive acquiescence by the Gov-
ernment before finding an agency relationship. See Ellyson, 326 F.3d
at 527-28. Our sister circuits have reasoned similarly. See, e.g.,
                        UNITED STATES v. JARRETT                          9
United States v. Smythe, 84 F.3d 1240, 1242-43 (10th Cir. 1996)
("[K]nowledge and acquiescence . . . encompass the requirement that
the government must also affirmatively encourage, initiate or instigate
the private action." (citation omitted) (emphasis added));3 United
States v. Koenig, 856 F.2d 843, 850 (7th Cir. 1988) ("It is only by the
exercise of some form of control that the actions of one may be attri-
buted to another. Mere knowledge of another’s independent action
does not produce vicarious responsibility absent some manifestation
of consent and the ability to control." (citations omitted)); Walther,
652 F.2d at 792 ("Mere governmental authorization of a particular
type of private search in the absence of more active participation or
encouragement is similarly insufficient to require the application of
fourth amendment standards." (citations omitted)).

   Viewed in the aggregate, then, three major lessons emerge from the
case law. First, courts should look to the facts and circumstances of
each case in determining when a private search is in fact a Govern-
ment search. Second, before a court will deem a private search a Gov-
ernment search, a defendant must demonstrate that the Government
knew of and acquiesced in the private search and that the private indi-
vidual intended to assist law enforcement authorities. Finally, simple
  3
    The Government contends that Smythe imposes a three-factor test,
mandating, in addition to the two factors stated in text, a requirement that
a defendant demonstrate that the Government has "affirmatively encour-
age[d], initiate[d] or instigate[d] the private action." Brief of Appellant
at 22. This argument ignores the language from Smythe emphasized
above. Nor do any of the other cases relied on by the Government as
requiring proof of a three-factor test so hold. Rather, they disavow "any
specific ‘standard’ or ‘test’" as too "oversimplified or too general to be
of help," see United States v. Pervaz, 118 F.3d 1, 6 (1st Cir. 1997), or
expressly recognize the two factors, which we have employed, as the
"[i]nitial[ ]" or "critical factors" and then cite evidence of Government
"encouragement" etc. simply as "[o]ther useful criteria." See United
States v. McAllister, 18 F.3d 1412, 1417-18 (7th Cir. 1994); United
States v. Marlbrough, 922 F.2d 458, 462 (8th Cir. 1992). Thus, these
cases do not conflict with, or present any reason to change, our own
emphasis on the two principal factors, recognizing that evidence of Gov-
ernment encouragement or participation is of course relevant in deter-
mining the existence of the first factor, i.e., Government knowledge and
acquiescence sufficient to make a private person a Government agent.
10                      UNITED STATES v. JARRETT
acquiescence by the Government does not suffice to transform a pri-
vate search into a Government search. Rather, there must be some
evidence of Government participation in or affirmative encourage-
ment of the private search before a court will hold it unconstitutional.
Passive acceptance by the Government is not enough.

     With these principles in mind, we turn to the case at hand.

                                   III.

   With respect to factfinding, the district court found the facts as we
have recounted them above. The record adequately supports these
findings; certainly they are not clearly erroneous.

   The district court’s conclusions of law, however, present problems.
The court concluded that Unknownuser’s extensive post-search email
exchange with Agent Faulkner, together with the brief exchanges
between Unknownuser and Agent Duffy in November and December
2000 (one year prior to the Jarrett search) and May 2001 (seven
months prior to the Jarrett search), demonstrated that the Government
had an "ongoing relationship" with Unknownuser sufficient to make
Unknownuser an agent of the Government. Specifically, the court
held that in light of the Government’s collective efforts to praise
Unknownuser for his assistance, its repeated requests for further assis-
tance, its assurances that Unknownuser would not be prosecuted for
his hacking activities, and its refusal to suggest that Unknownuser
should cease hacking, "there was far more than mere knowledge on
the government’s part."

   Although, as the Government conceded at oral argument, the
Faulkner email exchange probably does constitute the sort of active
Government participation sufficient to create an agency relationship
going forward (absent other countervailing facts), the district court
erred in relying on this exchange to find that the Government knew
of and acquiesced in the Jarrett search. This is so because
Unknownuser’s email exchange with Faulkner took place after
Unknownuser had hacked into Jarrett’s computer, after the fruits of
Unknownuser’s hacking had been made available to the FBI, after
Jarrett’s home and computer had been searched, and after Jarrett him-
self had been arrested. Thus, Faulkner’s knowledge and acquiescence
                        UNITED STATES v. JARRETT                        11
was entirely post-search. Such after-the-fact conduct cannot serve to
transform the prior relationship between Unknownuser and the Gov-
ernment into an agency relationship with respect to the search of Jar-
rett’s computer.

   As for the November-December 2000 and May 2001 exchanges
between Unknownuser and Agent Duffy, although they did occur
prior to the Jarrett search, all of these exchanges were brief and took
place seven to twelve months before the Jarrett search. Moreover,
these exchanges consisted of nothing more than perfunctory expres-
sions of gratitude for Unknownuser’s assistance in the Steiger investi-
gation, assurances that Unknownuser would not be prosecuted should
he decide to testify as a witness in the Steiger trial, and a vague offer
of availability to receive more information in the future. Without
more, these exchanges do not suffice to create an agency relationship
that would embrace the Jarrett search. Were we to allow the Duffy
communications to effect such an agency relationship, virtually any
Government expression of gratitude for assistance well prior to an
investigation would effectively transform any subsequent private
search by the party into a Government search. We find no support for
such a position in the existing case law, and we decline to extend the
protections of the Fourth Amendment to embrace it.4

   Although the Government operated close to the line in this case, it
did not (at least on the evidence before the district court) demonstrate
the requisite level of knowledge and acquiescence sufficient to make
   4
     The district court and Jarrett cite only a single appellate decision
upholding a suppression ruling in a context at all similar to that at hand.
See United States v. Walther, 652 F.2d 788 (9th Cir. 1981). There, the
Ninth Circuit held that an airline employee who had previously worked
as a paid, confidential informant for the DEA, acted as a Government
agent when he searched an overnight case shipped via the airline with the
expectation that he would receive a reward. The court reasoned that "the
government cannot knowingly acquiesce in and encourage directly or
indirectly a private citizen to engage in activity which it is prohibited
from pursuing where that citizen has no motivation other than the expec-
tation of reward from his or her efforts." Id. at 793. Walther offers no
assistance to Jarrett. Unlike the informant in Walther, Unknownuser
never received any sort of reward for his efforts, nor did he ever appear
to expect such a reward.
12                     UNITED STATES v. JARRETT
Unknownuser a Government agent when he hacked into Jarrett’s
computer. When Unknownuser came forward with the Jarrett infor-
mation, he had not been in contact with the Government for almost
seven months, and nothing indicates that the Government had any
intention of re-establishing contact with him. The only communica-
tions that could possibly be construed as signaling an agency relation-
ship prior to the search of Jarrett’s computer (the Duffy
communications from November-December 2000 and May 2001)
were simply too remote in time and too tenuous in substance to bring
the Jarrett search within the scope of an agency relationship.

   That the Government did not actively discourage Unknownuser
from engaging in illicit hacking does not transform Unknownuser into
a Government agent. Although the Government’s behavior in this
case is discomforting,5 the Government was under no special obliga-
tion to affirmatively discourage Unknownuser from hacking. See
Coolidge, 403 U.S. at 488 ("[I]t is no part of the policy underlying the
Fourth and Fourteenth Amendments to discourage citizens from aid-
ing to the utmost of their ability in the apprehension of criminals.");
United States v. Souza, 223 F.3d 1197, 1202 (10th Cir. 2000) (holding
that police are under no duty to discourage citizens from conducting
searches of their own volition).

   At the end of the day, in order to bring Unknownuser within the
grasp of an agency relationship, Jarrett would have to show that the
Government made more explicit representations and assurances (as in
the post-hoc Faulkner emails) that it was interested in furthering its
relationship with Unknownuser and availing itself of the fruits of any
information that Unknownuser obtained. Although evidence of such
"encouragement" would not have to target a particular individual, it
would have to signal affirmatively that the Government would be a
ready and willing participant in an illegal search.

  5
   Notwithstanding the Government’s assumptions, nothing in the record
establishes that Unknownuser is a foreign national and, even if he is, of
course, foreign nationals can, as the Government conceded, be prose-
cuted in the United States for sending and receiving child pornography.
Unauthorized hacking also violates United States law.
                       UNITED STATES v. JARRETT                      13
  As the facts in this case make clear, no such relationship existed
between Unknownuser and the Government when Unknownuser
hacked into Jarrett’s computer. Accordingly, we hold that the district
court erred when it found that Unknownuser acted as an agent of the
Government when he hacked into Jarrett’s computer.

                                  IV.

   For the reasons set forth within, we reverse the judgment of the dis-
trict court suppressing the evidence obtained from William Jarrett’s
residence and remand for further proceedings consistent with this
opinion.

                                        REVERSED AND REMANDED
