United States v. Eldred , 933 F.3d 110 ( 2019 )


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  • 17‐3367‐cv
    United States v. Eldred
    UNITED STATES COURT OF APPEALS
    FOR THE SECOND CIRCUIT
    August Term 2018
    (Argued: October 24, 2018               Decided: August 5, 2019)
    No. 17‐3367‐cv
    ––––––––––––––––––––––––––––––––––––
    UNITED STATES OF AMERICA
    Appellee,
    ‐v.‐
    ROBERT CLAY ELDRED
    Defendant‐Appellant.
    ––––––––––––––––––––––––––––––––––––
    Before:          LIVINGSTON, CHIN, Circuit Judges, and CROTTY, District Judge.
    Defendant‐Appellant Robert Clay Eldred (“Eldred”) was indicted on June
    23, 2016 for knowingly accessing child pornography. He moved to suppress
    evidence collected with the use of a government search program, the Network
    Investigative Technique (“NIT”), which aided in the identification of his computer
    despite his use of anonymizing software, saying the warrant that authorized use
    of the NIT was invalid. His motion was denied, and he pled guilty while
    
    Judge Paul A. Crotty, of the United States District Court for the Southern
    District of New York, sitting by designation.
    1
    reserving his right to appeal the district court’s decision to deny suppression. We
    agree with the district court that, regardless whether the warrant violated Federal
    Rule of Criminal Procedure 41(b) and the Federal Magistrates Act, 28 U.S.C. § 636,
    and whether such violations are also violative of the Fourth Amendment, law
    enforcement officers acted in good faith in applying for and carrying out the
    warrant. Accordingly, the judgment of the district court is AFFIRMED.
    FOR APPELLEE:                         BARBARA A. MASTERSON (Gregory L.
    Waples, on the brief), Assistant United States
    Attorneys, for Christina E. Nolan, United
    States Attorney for the District of Vermont,
    Burlington, Vermont.
    FOR DEFENDANT‐APPELLANT:              BARCLAY T. JOHNSON (David L. McColgin,
    on the brief), Assistant Federal Public
    Defenders, for Michael L. Desautels, Federal
    Public Defender for the District of Vermont,
    Burlington, Vermont.
    DEBRA ANN LIVINGSTON, Circuit Judge:
    This case arises from one of the many prosecutions following the
    investigation by the Federal Bureau of Investigation (“FBI”) into Playpen, a child
    pornography site located on the dark web. The FBI infiltrated the website and
    discovered the identities of many registered users by deploying a search program,
    the Network Investigative Technique (“NIT”), which allowed the FBI to
    circumvent the anonymizing features of the dark web and collect computer‐
    related identifying information, including internet protocol (“IP”) addresses, from
    the computers of these Playpen users. Defendant‐Appellant Robert Clay Eldred
    2
    (“Eldred”), whose information was collected by the NIT, moved to suppress
    evidence gathered by the program, arguing that the warrant authorizing it was
    invalid.   This motion was denied.            Like the nine other circuits to have
    considered the question thus far, we conclude that Eldred’s claim is without merit:
    even assuming, arguendo, that the NIT warrant violated the Fourth Amendment,
    law enforcement officers acted in good faith and suppression is not warranted.
    We therefore AFFIRM the judgment of the district court.
    BACKGROUND
    I.   Factual Background1
    Playpen operated on the “The Onion Router” (better known as “Tor”), an
    “anonymizing network” that allows users who have downloaded the Tor software
    to access websites without revealing their IP addresses or other identifying
    information by routing their internet traffic through numerous relay computers
    located around the world before such traffic arrives at a desired web location.
    These relay computers, which are owned by volunteers who donate their
    bandwidth to Tor, are known as “nodes.” Because of this indirect routing, when
    1 The factual background presented here is derived from the parties’ filings and
    testimony and evidence before the district court at the suppression hearing, held on
    January 19, 2017.
    3
    someone—for example, a law enforcement officer—attempts to view a Tor user’s
    IP address in order to identify the user’s computer and ascertain its whereabouts,
    the IP address displayed is actually that of the Tor “exit node,” i.e., the last
    computer through which the user’s traffic was relayed, rather than the actual
    address of the Tor user. Tor was originally developed and deployed by the U.S.
    Naval Research Laboratory to protect government communications, but it is now
    used by the public at large.
    Certain websites on Tor, called “hidden services,” are available only to Tor
    users on the Tor network. Instead of a typical web address, these hidden services
    are assigned a randomly generated list of characters ending with the suffix
    “.onion.” Law enforcement cannot determine the location of computers hosting
    these hidden services using traditional IP lookup techniques. As these websites
    are not indexed on the traditional Internet, they also don’t appear in searches run
    using traditional search engines—a Tor user must know the web address in order
    to access a hidden service. Playpen was one such website.
    When a Tor user typed Playpen’s “.onion” address into Tor and arrived at
    the site’s homepage for the first time, he was required to register with a username
    and password in order to enter the site. By clicking on the “register an account”
    4
    hyperlink, new users accessed a Playpen message instructing them that: (1) while
    “[t]he software we use for this forum requires that new users enter an email
    address . . . the forum operators do NOT want you to enter a real address”; (2)
    users should refrain from posting any information that could be used to identify
    them; and (3) that “it is impossible for the staff or the owners of this forum to
    confirm the true identity of users . . . .”   Joint Appendix (“J.A.”) 47.    After
    successfully registering, users could access a variety of child pornography,
    including images and videos indexed according to victim age, gender, and type of
    sexual activity depicted, as well as content related to child pornography.
    Although several of the site’s forums involved general information and rules
    regarding the site, Playpen as a whole was “dedicated to the advertisement and
    distribution of child pornography,” 
    id. at 43,
    and included forums in which users
    exchanged information about obtaining child pornography and engaging in child
    sexual abuse. In addition to images and discussions, Playpen also contained a
    private message feature.    Available historical data suggests that Playpen had
    over 1,500 unique users a day and over 150,000 registered users.
    The FBI began investigating Playpen in September 2014. In January 2015,
    FBI agents obtained a search warrant allowing the FBI to seize a copy of the server
    5
    hosting Playpen, which it installed on a server at a government facility in Virginia.
    On February 19, 2015, the FBI executed a court‐authorized search on the Naples,
    Florida home of the suspected administrator of the Playpen site. At that point
    the FBI was able to assume administrative control of Playpen. However, because
    of the anonymizing features of the Tor network, even with control of the website,
    the FBI could not identify other administrators or site users.
    For this reason, the FBI had developed the NIT, computer code which was
    added to the digital content of the copy of the Playpen website residing on the
    government server in Virginia. Once the NIT was deployed, whenever Tor users
    accessed Playpen and downloaded content so as to display it on their computers,
    that content was augmented with a set of computer instructions that traveled with
    it, through Tor’s network of relay computers, until coming to rest on the computer
    of the Playpen user.    When the NIT reached the Playpen user’s computer, the
    attached instructions executed, causing the user’s computer to transmit
    identifying information back to the government server in Virginia, including, inter
    alia, an IP address, the type of operating system employed by the computer and
    an active operating system username, and information regarding whether the NIT
    had previously been delivered.
    6
    On February 20, 2015, in the Eastern District of Virginia, where the
    government server then hosting Playpen was located, Magistrate Judge Theresa
    Carroll Buchanan issued a warrant to deploy the NIT (the “NIT warrant”). An
    attachment to the warrant listed the “[p]lace to be [s]earched” as “activating
    computers,” i.e., “those of any user or administrator who logs into the [Playpen
    website] by entering a username and password.”           J.A. 32.   The NIT would
    collect from all “activating computers,” wherever located, their actual IP
    addresses, as well as other specified pieces of information. While doing so, the
    NIT would not deny the users any functionality on their computers, or collect any
    additional, unrelated information. The listed information could then be used to
    identify the Playpen user’s true identity and location. Acting under authority of
    the NIT warrant, the FBI operated Playpen for about two weeks, from February 20
    until March 4, 2015, from the server in the Eastern District of Virginia.
    On March 4, 2015, a Playpen user identified only by the username
    “robertecach” entered the site and thereafter spent over an hour accessing three
    separate posts that contained images of prepubescent girls involved in genital
    exposure, oral sex, and penetration by what appeared to be an adult male penis.
    Through the use of the NIT, the FBI learned the IP address associated with
    7
    “robertecach,” as well as the fact that the computer name for the device that
    accessed the site was “Robert.” Agents traced the IP address to an address in East
    Montpelier, Vermont. Further investigation revealed that the house located at
    that address comprised two residences, one in the basement.        An FBI agent
    thereafter interviewed the owners, who listed Eldred among previous tenants of
    the basement unit and confirmed that he shared the house’s wireless connection
    with them.
    FBI agents visited Eldred’s subsequent residence in Northfield, Vermont on
    March 15, 2016, but found Eldred away at work. His girlfriend, Holly Belanger,
    and Eldred’s adult son were both present and spoke with the agents. Belanger
    confirmed that she and Eldred had lived at the address in East Montpelier in
    March 2015, and that Eldred still used the same laptop he had used at that time.
    She said that he had previously used the username “robertecache1” and that his
    laptop was password‐protected, while Eldred’s son said that Eldred had used the
    email address “robertecache@hotmail.com,” and that Eldred would not allow
    others to use his laptop. Agents called Eldred, who refused to consent to a search
    of his laptop but agreed to meet with agents the following day. The agents then
    seized the laptop.    After meeting with Eldred, who admitted he had used
    8
    “robertecach” as a previous email account and had lived in the East Montpelier
    basement apartment, the agents applied for and received a warrant from
    Magistrate Judge John M. Conroy in the United States District of Vermont to
    search the laptop. The search revealed 116 files relating to child pornography,
    including images of penile‐vaginal intercourse, penetration with objects, and oral
    sex.
    II.   Procedural History
    Eldred was indicted on June 23, 2016 for knowingly possessing child
    pornography in violation of 18 U.S.C. § 2252(a)(4)(B).     In November 2016 he
    moved to suppress all evidence and statements obtained as a result of the NIT
    warrant, arguing that it was invalid as Magistrate Judge Buchanan in the Eastern
    District of Virginia did not have jurisdiction to authorize searches outside of her
    district. He also moved to suppress evidence collected as a result of the Vermont
    warrant, arguing that it lacked probable cause.
    On February 17, 2017 Judge Geoffrey W. Crawford of the United States
    District Court for the District of Vermont denied Eldred’s motion to suppress in
    its entirety.   While he agreed with Eldred that the NIT warrant was issued in
    violation of Federal Rule of Criminal Procedure 41(b) (“Rule 41(b)”), Judge
    9
    Crawford concluded this rule violation was not of constitutional dimension.
    Citing this Court’s decision in United States v. Burke, 
    517 F.2d 377
    , 386‐87 (2d Cir.
    1975), the district court determined that application of the exclusionary rule was
    not warranted, given that no Fourth Amendment violation had occurred, Eldred
    had suffered no prejudice, and the FBI agents had not acted with deliberate
    disregard for Rule 41, but in good faith. Furthermore, the Vermont warrant was
    supported by probable cause.
    Eldred pled guilty, but reserved his right to challenge the district court’s
    denial of his motion to suppress. He was sentenced to six months in prison and
    a five‐year term of supervised release. He timely filed a motion to appeal.
    DISCUSSION
    On appeal from a district court’s ruling on a suppression motion, “we
    review a district court’s findings of fact for clear error, and its resolution of
    questions of law and mixed questions of law and fact de novo.” United States v.
    Bohannon, 
    824 F.3d 242
    , 247‐48 (2d Cir. 2016). Furthermore, we review a district
    court’s determination to apply the good‐faith exception based on an officer’s
    reliance on an issued warrant de novo. United States v. Raymonda, 
    780 F.3d 105
    ,
    113 (2d Cir. 2015).
    10
    On appeal, Eldred argues that the NIT warrant violated both Rule 41(b)2
    and the Federal Magistrates Act, 28 U.S.C. § 636(a).3            He further contends that
    because Magistrate Judge Buchanan lacked jurisdiction to issue the NIT warrant
    to search computers outside the Eastern District of Virginia, suppression should
    have been granted, and the good‐faith exception is either unavailable or
    inapplicable in this case. We note that after the NIT warrant issued, Rule 41(b)
    2  Rule 41(b) provides generally that a magistrate judge “has authority to issue a
    warrant to search for and seize a person or property located within the [magistrate
    judge’s] district,” but also authorizes the issuance of warrants pertaining to persons or
    property located outside the district in specified circumstances. At the time the NIT
    warrant was deployed, the Rule provided for issuance of the latter type of warrant for:
    (1) “a person or property outside the district if the person or property is located within
    the district when the warrant is issued but might move or be moved outside the district
    before the warrant is executed”; (2) in investigations of domestic or international
    terrorism; (3) for the installation within the district of a tracking device, to track
    movement of a person or property both within and without the district; and (4) for
    property located outside of any federal district. Fed. R. Crim. Pr. 41(b). None of these
    provisions “expressly allow[ed] a magistrate judge in one jurisdiction to authorize the
    search of a computer in a different jurisdiction.” United States v. Horton, 
    863 F.3d 1041
    ,
    1047 (8th Cir. 2017).
    3   Section 636(a) provides in relevant part as follows:
    Each United States magistrate judge serving under this
    chapter shall have within the district in which sessions are
    held by the court that appointed the magistrate judge, at other
    places where that court may function, and elsewhere as
    authorized by law – (1) all powers and duties conferred or
    imposed upon United States commissioners by law or by the
    Rules of Criminal Procedure for the United States District
    Courts . . . .
    11
    was amended specifically to authorize warrants such as the NIT warrant here.4
    However, as this subsection did not become effective until 2016, it cannot be said
    to have authorized the warrant in this case. Nevertheless, we conclude that it is
    unnecessary to address the majority of Eldred’s contentions as, agreeing with nine
    of our sister circuits, we ultimately conclude that even if the NIT warrant violated
    the Fourth Amendment, the good‐faith exception applies.5
    I
    Rapid technological change can affect both the opportunities for criminal
    behavior and its detection.          In recent years law enforcement officials with
    expertise in investigating child sexual exploitation have remarked on an increase
    4 The 2016 amendment added Rule 41(b)(6), which provides the following, in
    relevant part:
    [A] magistrate judge with authority in any district where
    activities related to a crime may have occurred has authority
    to issue a warrant to use remote access to search electronic
    storage media and to seize or copy electronically stored
    information located within or outside that district if . . . the
    district where the media or information is located has been
    concealed through technological means . . . .
    5  See United States v. Ganzer, 
    922 F.3d 579
    , 587‐90 (5th Cir. 2019); United States v.
    Moorehead, 
    912 F.3d 963
    , 967‐71 (6th Cir. 2019); United States v. Henderson, 
    906 F.3d 1109
    ,
    1117‐20 (9th Cir. 2018); United States v. Kienast, 
    907 F.3d 522
    , 526‐29 (7th Cir. 2018); United
    States v. Werdene, 
    883 F.3d 204
    , 215‐18 (3d Cir. 2018); United States v. McLamb, 
    880 F.3d 685
    , 690‐91 (4th Cir. 2018); United States v. Levin, 
    874 F.3d 316
    , 321‐24 (1st Cir. 2017); United
    States v. 
    Horton, 863 F.3d at 1049
    ‐52 (8th Cir. 2017); United States v. Workman, 
    863 F.3d 1313
    , 1317‐21 (10th Cir. 2017).
    12
    in the technological savvy of the perpetrators of such crimes, particularly in their
    use of anonymization methods. See Susan Hennessey, The Elephant in the Room:
    Addressing Child Exploitation and Going Dark, Hoover Institution, Aegis Paper Series
    No. 1701, at 5‐6 (2017). The proliferation of anonymization networks such as Tor
    has at the same time rendered “certain law enforcement techniques for electronic
    search and seizures . . . no longer effective.”      Jonathan Mayer, Government
    Hacking, 127 YALE L.J. 570, 577 (2017). Investigators who in the past “used to be
    able to subpoena an Internet Service Provider (ISP) for an online suspect’s
    identity,” 
    id., may today
    engage in more elaborate “watering hole” strategies of
    the sort employed in this case—where law enforcement agents operate a hidden
    service in order to deliver malware to identify suspects who “interact with the
    website under certain triggering conditions—for example, by visiting, logging in,
    or going to specific webpages,” 
    id. at 584.
    The debate between privacy and security in our era of rapidly changing
    technology is not new. See Carpenter v. United States, 
    138 S. Ct. 2206
    , 2233 (2018)
    (Kennedy, J., dissenting) (“Technological changes . . . have complex effects on
    crime and law enforcement.”). Nor is it novel to remark that rapid technological
    change poses the challenge of defending in new contexts the Fourth Amendment’s
    13
    fundamental “right of the people to be secure in their persons, houses, papers, and
    effects, against unreasonable searches and seizures.”      U.S. Const. amend IV.
    Even outside the dark web, “[t]he shift to a global Internet” is recognized to have
    “major implications” for Fourth Amendment law.           Orin S. Kerr, The Fourth
    Amendment and the Global Internet, 67 STAN. L. REV. 285, 288 (2015). In particular,
    the globalization of Internet traffic has left many asking just “how Fourth
    Amendment law should adapt to the reality of a global network in which suspects,
    victims, and evidence might be located anywhere.” 
    Id. at 289.
    This case is illustrative of the Fourth Amendment issues that can arise in
    Internet investigations involving dispersed actors in unknown physical locations.
    Eldred argues that the NIT warrant in this investigation, purporting to authorize
    “searches that were executed in judicial districts across the United States,” Def.‐
    App. Br. at 2, in fact “exceeded the magistrate judge’s territorial jurisdiction and
    violated Federal Rule of Criminal Procedure 41 and 28 U.S.C. § 636,” 
    id. at 15.
    Eldred further contends that because Magistrate Judge Buchanan lacked
    jurisdiction to issue the NIT warrant, it was void ab initio, and thus not a warrant
    at all, in Fourth Amendment terms.       Three of our nine sister circuits to have
    considered the NIT warrant have accepted at least aspects of this argument. See,
    14
    e.g., United States v. Henderson, 
    906 F.3d 1109
    , 1117 (9th Cir. 2018) (concluding that
    “a warrant purportedly authorizing a search beyond the jurisdiction of the issuing
    magistrate judge is void under the Fourth Amendment”); United States v. Werdene,
    
    883 F.3d 204
    , 214 (3d Cir. 2018) (“[T]he Rule 41(b) violation was of constitutional
    magnitude because at the time of the framing . . . a warrant issued for a search or
    seizure beyond the territorial jurisdiction of a magistrate’s powers under positive
    law was treated as no warrant at all.” (internal quotation marks omitted)); 
    Horton, 863 F.3d at 1049
    (“We . . . find that the NIT warrant was void ab initio, rising to the
    level of a constitutional infirmity.”).
    For the reasons set forth below, we need not address Eldred’s claim that the
    Fourth Amendment was violated by use of the NIT warrant. We note, however,
    that the issue is not clear cut.    Both Rule 41(b) and § 636(a) impose territorial
    constraints on the authority of magistrate judges to issue particular types of
    warrants, but the Fourth Amendment itself says nothing about where such
    authority may be exercised, nor whether a venue requirement exists as a matter of
    Fourth Amendment law.          See Dalia v. United States, 
    441 U.S. 238
    , 255 (1979)
    (noting that the Court has interpreted the Fourth Amendment “to require only
    three things”: issuance by a “neutral, disinterested magistrate[,]” probable cause,
    15
    and particularity). Some have grounded such a requirement in the concept of a
    “neutral and detached magistrate.” See United States v. Taylor, 
    250 F. Supp. 3d 1215
    , 1235 (N.D. Al. 2017) (“[I]nherent in the notion of a ‘neutral, detached
    magistrate’ is that the magistrate have authority to issue the warrant.” (emphasis
    omitted)); see also United States v. Krueger, 
    809 F.3d 1109
    , 1124 (10th Cir. 2015)
    (Gorsuch, J., concurring) (“The principle animating the common law at the time of
    the Fourth Amendment’s framing was clear: a warrant may travel only so far as
    the power of its issuing official.”).    But assuming, arguendo, that there is a
    constitutional dimension to some cases in which a warrant might exceed territorial
    limits set by statute or by rule, it is not clear that all such cases present viable
    Fourth Amendment claims, particularly in a technological context in which both
    crimes and the evidence to prove their commission are digitized, and detached
    from the offline locations of suspects, confederates, and victims.
    Here, for instance, even assuming that Magistrate Judge Buchanan in fact
    lacked jurisdiction to issue a NIT warrant to authorize the retrieval of information
    from computers located outside the Eastern District of Virginia, there is no dispute
    that she had authority as to computers within that district.    At least one sister
    circuit has determined, as a result, that the NIT warrant “was not void ab initio,
    16
    for the warrant could validly be executed by extracting data from computers
    within the magistrate judge’s district (the Eastern District of Virginia).” United
    States v. Workman, 
    863 F.3d 1313
    , 1318 n.1 (10th Cir. 2017) (emphasis added); but
    see 
    Horton, 863 F.3d at 1049
    (rejecting argument that “[t]he possibility that the
    magistrate could have executed a proper warrant in the Eastern District of Virginia
    . . . save[s] this warrant from its jurisdictional error); 
    Werdene, 883 F.3d at 214
    n.9
    (same).
    Several of the nine sister circuits to have addressed the NIT warrant here
    have noted that the situation that arose in this case will not recur due to the
    passage of the 2016 amendments to Rule 41(b). See, e.g., 
    Werdene, 883 F.3d at 218
    (“[E]ven though Rule 41(b) did not authorize the magistrate judge to issue the NIT
    warrant, future law enforcement officers may apply for and obtain such a warrant
    pursuant to Rule 41(b)(6), which went into effect in December 2016 to authorize
    NIT‐like warrants.”); see also Hennessey, Elephant in the Room, at 16 (“The
    December 1 rule change effectively moots the issue for future investigations.”).
    But even this point is not beyond doubt. In relevant part, the Federal Magistrates
    Act provides that a magistrate judge has the powers and duties conferred or
    imposed by the Rules of Criminal Procedure “within the district in which sessions
    17
    are held by the court that appointed the magistrate judge, at other places where
    that court may function, and elsewhere as authorized by law.” 28 U.S.C. § 636(a).
    Such language, in the view of some courts, “imposes independent territorial
    restrictions on the powers of magistrate judges” specifically, so that even
    assuming Rule 41(b) “grants to magistrate judges the power to do certain specified
    things,” this is only if otherwise permissible pursuant to the Federal Magistrates
    Act, “a question the rules themselves do not purport to answer and that can be
    answered only by circling back to § 636(a).” 
    Krueger, 809 F.3d at 1121
    (Gorsuch,
    J., concurring); see also 
    Henderson, 906 F.3d at 1115
    n.5 (referencing but declining to
    consider NIT warrant’s validity pursuant to the “independent territorial
    limitations imposed upon a magistrate judge’s jurisdiction by § 636 itself”). If the
    scope of Judge Buchanan’s authority to issue the NIT warrant “[wasn’t] merely
    one of rule, . . . [but] of statutory dimension,” 
    Krueger, 809 F.3d at 1122
    (Gorsuch,
    J., concurring), the recent amendments to Rule 41 may not alone be sufficient to
    answer the question whether a magistrate judge, as opposed to a district court
    judge, has authority to issue NIT‐style warrants pursuant to the amended Rule.
    See Mayer, Government Hacking, at 627‐28 (suggesting, as a result, that “[w]hen the
    government intends to search a computer but does not know the computer’s
    18
    location,” a warrant application should be submitted to a district court judge).
    Thus, the Fourth Amendment issues raised by Eldred could recur, but now
    pursuant to § 636(a) alone.
    But that issue is not before us today. Nor need we determine whether the
    NIT warrant in this case in fact issued in violation of the pre‐amendment Rule 41(b)
    or § 636(a) of the Federal Magistrates Act. For as we discuss below, regardless
    whether Magistrate Judge Buchanan exceeded the scope of her jurisdiction
    pursuant to either of these provisions, we agree with the nine previous circuits to
    have considered the issue and conclude that suppression is not warranted because
    the good‐faith doctrine applies.
    II
    The Fourth Amendment protects the “right of the people to be secure in
    their persons, houses, papers, and effects, against unreasonable searches and
    seizures.” U.S. Const. amend IV. To effectuate this right, courts have created
    an exclusionary rule “that, when applicable, forbids the use of improperly
    obtained evidence at trial.”   Herring v. United States, 
    555 U.S. 135
    , 139 (2009).
    Nevertheless, “the exclusionary rule is not an individual right and applies only
    where it results in appreciable deterrence.” 
    Id. at 141
    (internal quotation marks
    19
    and brackets omitted). “[E]vidence obtained in objectively reasonable reliance
    on a subsequently invalidated search warrant cannot justify the substantial costs
    of exclusion” and will not be suppressed. United States v. Leon, 
    468 U.S. 897
    , 922
    (1984); see also Davis v. United States, 
    564 U.S. 229
    , 238 (2011) (noting that exclusion
    is not required when police act “with an objectively reasonable good‐faith belief
    that their conduct is lawful” or when police conduct “involves only simple,
    isolated negligence” (internal quotation marks omitted)).
    The good‐faith exception first recognized in Leon holds that when the agents
    executing a search warrant “act with an objectively reasonable good‐faith belief’
    that their conduct is lawful,” improperly obtained evidence remains admissible
    because in such circumstances, “the deterrence rationale loses much of its force,
    and exclusion cannot pay its way.”        
    Davis, 564 U.S. at 238
    (internal quotation
    marks omitted).        Granted, the Supreme Court in Leon delineated several
    situations in which the good‐faith exception does not apply :
    (1) the magistrate or judge “was misled by information in an affidavit that
    the affiant knew was false or would have known was false except for his
    reckless disregard of the truth”;
    (2) “where the issuing magistrate wholly abandoned his judicial role”;
    20
    (3) a warrant was based on an affidavit “so lacking in indicia of probable
    cause as to render official belief in its existence entirely unreasonable”; and
    (4) a warrant is so “facially deficient” that officers “cannot reasonably
    presume it to be valid.”
    
    Leon, 468 U.S. at 923
    (internal quotation marks omitted). These situations align
    broadly with the recognition that “[t]he extent to which the exclusionary rule is
    justified by . . . deterrence principles varies with the culpability of the law
    enforcement conduct.” 
    Herring, 555 U.S. at 143
    . But none of the circumstances
    recognized in Leon are applicable here.
    Eldred in fact makes no argument for any but the fourth. He contends that
    the NIT warrant was “facially deficient” because it—as opposed to the affidavit
    supporting the warrant’s application—was limited to the Eastern District of
    Virginia and did not encompass Vermont or the many other judicial districts to
    which the FBI’s computer instructions were delivered. Of course, “[t]he Fourth
    Amendment by its terms requires particularity in the warrant, not in the
    supporting documents.” Groh v. Ramirez, 
    540 U.S. 551
    , 557 (2004). But while we
    do not “rely on unincorporated, unattached supporting documents to cure a
    constitutionally defective warrant, those documents are still relevant to our
    21
    determination of whether the officers acted in good faith.” United States v. Rosa,
    
    626 F.3d 56
    , 64 (2d Cir. 2010). Here, we agree with the Eighth Circuit that upon
    reading the affidavit—which describes in great detail how the NIT was to work—
    “a reasonable reader would have understood that the search would extend beyond
    the boundaries of the district,” supporting the officers’ good faith reliance.
    
    Horton, 863 F.3d at 1052
    .
    Moreover, even if we exclude consideration of the affidavit as not
    sufficiently incorporated into the search warrant, as Eldred urges for the first time
    on appeal, the warrant itself does not contain clear geographic limitations on the
    place to be searched.       Quite the opposite—Attachment A to the NIT warrant
    refers to the place to be searched as all “activating computers,” defined in relevant
    part as “any user . . . who logs into” Playpen. J.A. 32 (emphasis added). We thus
    agree with the Eighth Circuit again that there is no “obvious deficiency” in the
    warrant, which a number of courts have found facially valid. 
    Horton, 868 F.3d at 1052
    ; see also 
    Leon, 468 U.S. at 923
    (observing that a “facially deficient” warrant
    merits exclusion when “the executing officers cannot reasonably presume it to be
    valid”).
    We also disagree with Eldred that actions taken by the government
    22
    surrounding this warrant more broadly demonstrate the sort of “deliberate,
    reckless, or grossly negligent conduct” that the exclusionary rule exists to deter.
    
    Herring, 555 U.S. at 144
    .     To support this argument, Eldred points to the
    Department of Justice’s letter to the Advisory Committee on Criminal Rules
    urging an amendment to Rule 41(b), suggesting this letter demonstrates the
    government’s awareness that a NIT warrant like the one issued here did not fall
    within the scope of Rule 41 at that time. Furthermore, he suggests that because
    several different offices within the Department—and employees at different levels
    within those offices—reviewed the warrant before presenting it to Magistrate
    Judge Buchanan, we must differentiate a case like this from the typical case in
    which we decline to impute detailed knowledge of the law to police or other law
    enforcement officers. We turn to a sister circuit, the Fourth Circuit, which has
    previously addressed this very argument:
    [I]n light of rapidly developing technology, there will not
    always be definitive precedent upon which law
    enforcement can rely when utilizing cutting edge
    investigative techniques. In such cases, consultation
    with government attorneys is precisely what Leon’s
    “good faith” expects of law enforcement. We are
    disinclined to conclude that a warrant is “facially
    deficient” where the legality of an investigative
    technique is unclear and law enforcement seeks advice
    from counsel before applying for the warrant.
    23
    United States v. McLamb, 
    880 F.3d 685
    , 691 (4th Cir. 2018); see also United States v.
    Levin, 
    874 F.3d 316
    , 323 (1st Cir. 2017) (noting “no benefit in deterring” the
    government from “turn[ing] to the courts for guidance” when faced with a novel
    legal question such as whether an NIT warrant can issue). Moreover, like our
    sister circuits, “we do not construe the government’s efforts to have Rule 41(b)
    amended . . . as an admission that [NIT] warrants were not previously allowed,
    but rather as an attempt to clarify an existing law’s application to new
    circumstances.” United States v. Ganzer, 
    922 F.3d 579
    , 589 (5th Cir. 2019). The
    affidavit attached to the application for the NIT warrant in this case was over thirty
    pages long and explained the procedure of the NIT and the circumstances of the
    Playpen investigation in meticulous detail.           We do not see how such
    comprehensive disclosure by the government can be deemed a “knowing
    disregard” for the rules, Def.‐App. Br. at 56, even if a magistrate judge may have
    subsequently misunderstood her authority to grant such an application.
    Lastly, to the extent that Eldred argues the good faith exception
    categorically cannot apply when a warrant is issued by a judge lacking jurisdiction
    and is thus void ab initio, we do not agree. Again, we need not—and do not—
    pass on the issue whether the warrant here was void ab initio, and for this reason
    24
    violative of the Fourth Amendment.        See 
    Herring, 555 U.S. at 141
    (separating
    analysis of potential constitutional violation from application of exclusionary
    rule). Eldred’s proposed categorical exclusion from the good faith exception is
    easily disposed of, even assuming arguendo that the NIT warrant was
    constitutionally infirm.
    As the Supreme Court has repeatedly stated, the exclusionary rule cannot
    be used to penalize law enforcement officers for a magistrate’s error. See 
    Leon, 468 U.S. at 921
    (“Penalizing the officer for the magistrate’s error, rather than his own,
    cannot logically contribute to the deterrence of Fourth Amendment violations.”);
    see also 
    Davis, 564 U.S. at 246
    (“[W]e have said time and again that the sole purpose
    of the exclusionary rule is to deter misconduct by law enforcement.”);
    Massachusetts v. Sheppard, 
    468 U.S. 981
    , 989‐90 (1984) (“[W]e refuse to rule that an
    officer is required to disbelieve a judge who has just advised him, by word and by
    action, that the warrant he possesses authorizes him to conduct the search he has
    requested.”). In Leon, for instance, the Supreme Court upheld the use of evidence
    collected in reliance on a search warrant that a magistrate judge had erroneously
    issued despite the absence of probable cause.        
    See 468 U.S. at 925
    ‐26.     The
    constitutional deficiencies of that warrant did not require exclusion of the evidence
    25
    thereby obtained because the officers’ reasonable reliance on the warrant did not
    implicate the deterrent purposes of the exclusionary rule.          Even assuming,
    arguendo, that statutory or rule limitations on a magistrate judge’s jurisdiction also
    rise to the level of independent constitutional requirements, we see no reason to
    treat a magistrate judge’s non‐compliance with these requirements differently
    than non‐compliance with a fundamental Fourth Amendment constraint on the
    issuance of warrants, such as probable cause.
    We therefore agree with our sister circuits that the good‐faith exception is
    applicable even when a warrant is void ab initio, so long as the law enforcement
    agents executing such a warrant had an objectively reasonable belief that it was
    valid. See 
    Horton, 863 F.3d at 1050
    ; see also 
    Henderson, 906 F.3d at 1118
    (rejecting
    inapplicability of good‐faith exception to warrant that is void ab initio because
    “good faith exception does not depend on the existence of a warrant, but on the
    executing officers’ objectively reasonable belief that there was a valid warrant”);
    United States v. Kienast, 
    907 F.3d 522
    , 528 (7th Cir. 2018) (noting that “whether the
    magistrate judge lacked authority has no impact” on availability of good‐faith
    exception for police). The exception properly “applies to warrants that are void
    ab initio” in such circumstances because “‘the issuing magistrate’s lack of authority
    26
    has no impact on police misconduct.’” 
    Werdene, 883 F.3d at 216
    (quoting United
    States v. Master, 
    614 F.3d 236
    , 242 (6th Cir. 2010)). We thus join our sister circuits
    in upholding the district court’s application of the good‐faith exception in this
    case.
    CONCLUSION
    We have considered Eldred’s remaining arguments and deem them waived
    or without merit. For the foregoing reasons, we AFFIRM the judgment of the
    district court.
    27