Affirmеd in part and remanded in part by published opinion. Judge WILKINS wrote the opinion, in which Judge NIEMEYER and Judge SEYMOUR joined.
OPINION
Mark L. Simons appeals his convictions for receiving and possessing materials constituting or containing child pornography, see 18 U.S.C.A. § 2252A(a)(2)(A), (a)(5)(B) (West Supp.1999). Simons, who received the unlawful materials at his government workplace via the Internet, argues that the district court erred in denying his motion to suppress. We affirm in part and remand in part.
I.
Simons was employed as an electronic engineer at the Foreign Bureau of Information Services (FBIS), a division of the Central Intelligence Agency (CIA). FBIS provided Simons with an office, which he did not share with anyone, and a computer with Internet access.
In June 1998, FBIS instituted a policy regarding Internet usage by employees. The policy stated that employees were to use the Internet for official government business only. Accessing unlawful material was specifically prohibited. The policy explained that FBIS would conduct electronic audits to ensure compliance:
Audits. Electronic auditing shall be implemented within all FBIS unclassified networks that connect to the Internet or other publicly accessible networks to support identification, termination, and prosecution of unauthorized activity. These electronic audit mechanisms shall ... be capable of recording:
*396 • Access to the system, including successful and failed login attempts, and logouts;
• Inbound and outbound file transfers;
• Terminal connections (telnet) to and from external systems;
• Sent and received e-mail messages;
• Web sites visited, including uniform resource locator (URL) of pages retrieved;
• Date, Time, and user associated with each event.
J.A. 125-26. The policy also stated that “[u]sers shall ... [u]nderstand FBIS will periodically audit, inspect, and/or monitor the user’s Internet access as deemed appropriate.” J.A. 127.
FBIS contracted with Science Applications International Corporation (SAIC) for the management of FBIS’ computer network, including monitoring for any inappropriate use of computer resources. On July 17, 1998, Clifford Mauck, a manager at SAIC, began exploring the capabilities of a firewall recently acquired by SAIC, because Mauck believed that SAIC needed to become more familiar with the firewall to service the FBIS contract properly. 1 Mauck entered the keyword “sex” into the firewall database for July 14 and 17, 1998, and found a large number of Internet “hits” originating from Simons’ computer. It was obvious to Mauck from the names of the sites that they were not visited for official FBIS purposes.
Mauck reported this discovery to his contact at FBIS, Katherine Camer. Cam-er then wоrked with another SAIC employee, Robert Harper, to further investigate the apparently unauthorized activity. Camer instructed Harper to view one of the websites that Simons had visited. Harper complied and found that the site contained pictures of nude women.
At Camer’s direction and from his own workstation, Harper examined Simons’ computer to determine whether Simons ■ had downloaded any picture files from the Internet; Harper found over 1,000 such files. Again from his own workstation, Harper viewed several of the pictures and observed that they were pornographic in nature. Also at Camer’s request and from his оwn workstation, Harper printed a list of the titles of the downloaded picture files. Harper was then asked to copy all of the files on the hard drive of Simons’ computer; Harper accomplished this task, 'again, from his own workstation.
On or about July 31,1998, two representatives from the CIA Office of the Inspector General (OIG), one of whom was a criminal investigator, viewed selected files from the copy of Simons’ hard drive; the pictures were of minors. Later that day, Harper physically entered Simons’ office, removed the original hard drive, replaced it with a copy, and gave the original to the FBIS Area Sеcurity Officer. The Security Officer turned it over to the OIG criminal investigator the same day. 2 This last assignment was the only one that required Harper to physically enter Simons’ office.
On August 5, 1998, FBI Special Agent John Mesisca viewed over 50 of the images on the hard drive that had been removed from Simons’ office; many of the images contained child pornography. Mesisca, Harper, the two OIG representatives, and Assistant United States Attorney Tom Connolly worked together to prepare an application for a warrant to search Simons’ office and computer. An affidavit from Mesisca supported the warrant аpplication. The affidavit stated, inter alia, that Si-mons had connected a zip drive to his computer. 3 The affidavit also expressed a *397 “need” to conduct the search in secret. J.A. 140..
The warrant was issued on August 6, 1998. It stated that the executing officers were to leave at Simons’ office a copy of the warrant and a receipt for any property taken. The warrant mentioned neither permission for, nor prohibition of, secret execution.
Mesisca and others executed the search during the evening of August 6, 1998, when Simons was not present. The search team copied the contents of Simons’ computer; computer diskettes found in Si-mons’ desk drawer; computer files stored on the zip drive or on zip drive diskettes; 4 videotapes; and various documents, including personal correspondence. No original evidence was removed from the office. Neither a copy of the warrant nor a receipt for the property seized was left in the office or otherwise given to Simons at that time, and Simons did not learn of the search for approximately 45 days. 5 When Mesisca reviewed the computer materials copied during the search, he found over 50 pornographic images of minors.
In September 1998, Mesisca applied for a second search warrant. The supporting affidavit, like the affidavit that supported the August application, stated that Simons had connected a zip drive to his computer. The September affidavit described the August application as an application for a surreptitious search warrant.
A second search warrant was obtained on September 17, 1998 and executed on September 23, 1998, with Simons present. Original evidence was seized and removed from the office. The executors left Simons with a copy of the warrant and an inventory of the items seized.
Simons subsequently was indicted on one count of knowingly receiving child pornography that had been transported in interstate commerce, see 18 U.S.C.A. § 2252A(a)(2)(A), and onе count of knowingly possessing material containing images of child pornography that had been transported in interstate commerce, see 18 U.S.C.A. § 2252A(a)(5)(B). Simons moved to suppress the evidence, arguing that the searches of his office and computer violated his Fourth Amendment rights. Following a hearing, the district court denied the motion. With regard to the warrantless searches, the district court first concluded that Simons lacked a legitimate expectation of privacy in his Internet use. The court nevertheless determined that, even if Simons did have a legitimate expectation of privacy, all of the warrantless searches satisfied the reasonableness requirement of the Fourth Amendment. The district court also upheld the warrant searches.
At a bench trial on stipulated facts, four computer picture files depicting child pornography were introduced as evidence of Simons’ guilt. The district court found Simons guilty on both counts and sentenced him to 18 months imprisonment. Simons now appeals, maintaining that the district court erred in denying his motion to suppress.
Inexplicably, the record does not indicate which search or searches yielded the four computer picture files used against Simons at trial. Consequently, we are called uрon to review the constitutionality of all of the searches. We consider first the warrantless searches, then turn to Si-mons’ challenges to the searches conducted pursuant to the August search warrant. 6
*398 II.
The Fourth Amendment prohibits “unreasonable searches and seizures” by government agents, including government employers or supervisors. U.S. Const, amend. IV;
see O’Connor v. Ortega,
Government employees may have a legitimate expectation of privacy in their offices or in parts of their offices such as their desks or file cabinets.
See O’Connor,
We first consider Simons’ challenge to the warrantless searches of his computer and office by FBIS. 7 We conclude that the remote searches of Simons’ computer did not violate his Fourth Amendment rights because, in light of the Internet policy, Simons lacked a legitimate expectation of privacy in the files downloaded from the Internet. Additionally, we conclude that Simons’ Fourth Amendment rights were not violated by FBIS’ retrieval of Simons’ hard drive from his office.
Simons did not have a legitimate expectation of privacy with regard to the record or fruits of his Internеt use in light of the FBIS Internet policy. The policy clearly stated that FBIS would “audit, inspect, and/or monitor” employees’ use of the Internet, including all file transfers, all websites visited, and all e-mail messages, “as deemed appropriate.” J.A. 127. This policy placed employees on notice that they could not reasonably expect that their Internet activity would be private.
8
Therefore, regardless of whether Simons subjectively believed that the files he transferred from the Internet were private, such a belief was not objectively reasonable after FBIS notified him that it would be overseeing his Internet use.
9
Sеe American Postal Workers Union v. United States Postal Sew.,
We next consider whether Harper’s warrantless entry into Simons’ office to retrieve his hard drive violated the Fourth Amendment. The district court did not separately address this search; rather, it evaluated all of the warrantless searches together. Although we agree with the district court that Simons lacked a legitimate expectation of privacy in his Internet use, and thus in the hard drive itself, Harper’s entry into Simons’ office to retrieve the hard drive presents a distinct question.
See United States v. Horowitz,
The burden is on Simons to prove that he had a legitimate expectation of privacy in his office.
See Rusher,
Consequently, we must determine whether FBIS’ warrantless entry into Simons’ office to retrieve the hard drive was reasonable under the Fourth Amendment. A search conducted without a warrant issued by a judge or magistrate upon a showing of probable cause is
“per se
unreasonable” unless it falls within one of the “specifically established and well-
*400
delineated exceptions” to the warrant requirement.
Katz v. United States,
The question thus becomes whether the search of Simons’ office falls within the ambit of the
O’Connor
exception to the warrant requirement,
i.e.,
whether the search was carried out for the purpose of obtaining “evidence of suspected work-related employee misfeasance.”
Id.
at 723,
As it does not appear from the record that FBIS utilized the hard drive for internal investigatory purposes before turning it over to the criminal investigator at OIG, we will assume that the dominant purposes of the warrantless search of Simons’ office was to acquire evidence of criminal activity, which had been committed at FBIS using FBIS equipment. Nevertheless, the search remains within the
O’Connor
exception to the warrant requirement; FBIS did not lose its special need for “the efficient and proper operation of the workplace,”
id.,
merely because the evidence obtained was evidence of a crime.
Cf. New York v. Burger,
We have little trouble concluding that the warrantless entry of Simons’ office was reasonable under the Fourth Amendment standard announced in
O’Connor.
At the inception of the search FBIS had “reasonable grounds for suspecting” that the hаrd drive would yield evidence of misconduct because FBIS was already aware that Si-mons had misused his Internet access to download over a thousand pornographic images, some of which involved minors.
O’Connor,
In the final analysis, this case involves an employee’s supervisor entering the employee’s government office and retrieving a piece of government equipment in which the employee had absolutely no expectation of privacy — equipment that the employer knew contained evidence of crimes committed by the employee in the employee’s office. This situation may be contrasted with one in which the criminal acts of a government employee were unrelated to his employment. Here, there was a conjunction of the conduct thаt .violated the employer’s policy and the conduct that violated the criminal law. We consider that FBIS’ intrusion into Simons’ office to retrieve the hard drive is one in which a reasonable employer might engage.
See Vernonia School Dist. 47J,
For the foregoing reasons, we agree with the district court that Simons’ Fourth Amendment rights were not violated by any of FBIS’ activities in searching his computer and office.
III.
Simons also challenges the search conducted pursuant to the August search warrant. We reject Simons’ arguments that the search violated his constitutional rights. However, we remand for further proceedings concerning Simons’ claim that the search team violated Federal Rule of Criminal Procedure 41(d) when it failed to leave, at the time of the search, a copy of the warrant or a receipt for the property taken.
Simons first alleges that the warrant was invalid as to the zip drive and zip drive diskettes because the affidavit supporting the warrant application contained a deliberately misleading statement — that Simons had attached a zip drive to his computer. At the suppressiоn hearing, Mauck stated that he did not know whether a zip drive was connected to Simons’ computer, and Harper essentially testified that he did not believe there was a zip drive connected to Simons’ computer. Because at least Harper participated in preparing the warrant application, Simons attributes the knowledge of these SAIC employees to Mesisca, the author of the affidavit. Simons argues that the affidavit therefore contained a knowingly false statement and that the statement impermissibly expanded the scope of the search because without the statement there was no probable cause to search the zip drive or zip drive diskettes.
“[I]n all cases outside the exceptions to the warrant requirement the
*402
Fourth Amendment requires the interposition of a neutral and detached magistrate between the police and the persons, houses, papers, and effects of citizens.”
Thompson v. Louisiana,
Simons has failed to satisfy these threshold requirements. He has introduced no evidence showing that Mesisca made the statement regarding the zip drive deliberately or with reckless disregard for the truth, nor has he shown that the statement was critical to the finding of probable cause. At most, the scope of the misstatement was that the zip drive was connected to the computer. As the magistrate judge found probable cause to search other items in the office not connected to the computer, whether the zip drive was actually connected to the computer was obviously not essential to the probable cause determination. We therefore conclude that the statement in the affidavit regarding the zip drive being connected to the computer did not render the seizure of the zip drive and zip drive diskettes unlawful. 12
Next, Simons argues that the August search violated the Fourth Amendment and Federal Rule of Criminal Procedure 41(d) because the search team executing the warrant left neither a copy of the warrant nor a receipt for the property taken. We conclude that these fadings did not violate Simons’ constitutional rights, but we remand for the district court to determine whether the executors of the warrant delibеrately violated Rule 41(d).
Federal Rule of Criminal Procedure 41(d) provides, in pertinent part, that
[t]he officer taking property under the warrant shall give to the person from whom or from whose premises the property was taken a copy of the warrant and a receipt for the property taken or shall leave the copy and receipt at the place from which the property was taken.
Fed.R.Crim.P. 41(d). The August search warrant stated substantially the same requirements. However, the search team that executed the warrant left neither a copy of the warrant nor a receipt for the property taken. Therefore, it is clear that the executors of the warrant violated Rule 41(d). Simons argues that the fadure to leave notice of the search violated his Fourth Amendment rights and was a deliberate violation of Rule 41(d); he maintains that suppression is an appropriate remedy.
*403
There are two categories of Rule 41 violations: those involving constitutional violations, and all others.
See United States v. Chaar,
First, we conclude that the failure of the team executing the warrant to leave either a copy of the warrant or a receipt for the items taken did not render the search unreasonable under the Fourth Amendment. The Fourth Amendment does not mention notice, and the Supreme Court has stated thаt the Constitution does not categorically proscribe covert entries, which necessarily involve a delay in notice.
See Dalia v. United States,
Having concluded that thе Rule 41(d) violation at issue here did not infringe on Simons’ constitutional rights, we must now evaluate his argument that the violation was deliberate. 13 As described above, the affidavit supporting the August warrant application stated a “need” to conduct the search in secret. J.A. 140. However, the warrant required its executors to leave a copy of the warrant and a receipt for the property taken. Based on these facts, Simons argues that the search team applied for, but the magistrate judge denied, a warrant to conduct a secret search. Simons further maintains that the team deliberately circumvented the denial of its request when it failed to leave notice of the search. The Government responds that the search team applied for and believed that it had received a warrant that authorized a secret search.
The district court did not address the intent issue when it ruled on Simons’ motion to suppress, and as a factual matter it is beyond our province on appeal. We therefore remand for the district court to consider whether the Government intentionally and deliberately disregarded the notice provision of Rule 41(d) when it carried out the August 6,1998 search.
IV.
We conclude that FBIS’ searchеs of Si-mons’ computer and office did not violate Simons’ Fourth Amendment rights. We also determine that the August search warrant was valid and that the violation of Rule 41(d) did not render the search constitutionally unreasonable. However, we remand for the district court to consider *404 whether Rule 41(d) was intentionally and deliberately disregarded.
AFFIRMED IN PART, REMANDED IN PART
Notes
. A firewall is like a funnel through which all Internet access flows and is registered; the firewall collects data and may be searched as a database.
. The OIG investigator “placed it into evidence.” J.A. 70.
.A zip drive is a device for storing computer files; it has greater storage capacity than other computer storage devices. Zip drive diskettes work only in zip drives and not with other computer storage devices.
.The parties agree that materials associated with the zip drive were copied during the search, but the record is not clear as to whether the materials actually came from the zip drive itself or from zip diskettes. Resolution of this factual matter is not necessary to decide this appeal.
. A property list was returned to the magistrate judge, as required.
. Simons also challenges the search conducted pursuant to the September search warrant. We address his arguments with regard to this search infra, in note 12.
.Although an SAIC employeе conducted the searches, for ease of reference and in light of the fact that SAIC was an FBIS contractor, we refer to the searches as having been carried out by FBIS.
Also, Simons has focused exclusively on the warrantless nature of these searches; he has not argued that the searches were not supported by probable cause. We therefore limit our discussion to the warrantless nature of the searches.
. Simons does not assert that he was unaware of, or that he had not consented to, the Internet policy.
. Simons attempts to distinguish the files downloaded from the Internet from the recоrd of those downloads registered on the firewall, and argues that he had a legitimate expectation of privacy in the former. We decline to recognize the distinction Simons advocates.
. The Internet policy did not render Simons’ expectation of privacy in his office unreasonable. The policy does not mention employees’ offices, and although it does not prohibit FBIS from carrying out its "auditing], inspect[ing], and/or monitor[ing]” activities at employees’ individual workstations, J.A. 127, this fact alone is insufficient to render unreasonable an employee’s subjective expectation of privacy in his оffice.
Cf. Schowengerdt v. United States,
Although the CIA may have had other policies that rendered unreasonable any expectation of privacy in an office occupied by an employee, such as Simons, with access to classified information, no such policies were made a part of this record and consequently we must assume that none existed.
. While we are not impressed with the degree to which this issue was factually developed in the district court, remand for further factual development is not appropriate as the issue was clearly rаised and both parties had an opportunity to introduce evidence on the matter.
. We reject the same argument with regard to the application for the September warrant. Simons also argues that the September application contained an additional knowing misrepresentation because the affidavit described the August application as one for a surreptitious search warrant. Regardless of whether there is any evidence that Mesisca made this statement deliberately, or with reckless disregard for the truth, there is no reason to suspect that the statement affected the probable cause determination.
. Simons does not maintain on appeal that he was prejudiced by the Rule 41(d) violation.
