UNITED STATES COURT OF APPEALS May 12, 2025

Christopher M. Wolpert FOR THE TENTH CIRCUIT Clerk of Court _________________________________

UNITED STATES OF AMERICA,

Plaintiff - Appellee,

v. No. 23-2017

GUY ROSENSCHEIN,

Defendant - Appellant. _________________________________

Appeal from the United States District Court for the District of New Mexico (D.C. No. 1:16-CR-04571-JCH-1) _________________________________ Submitted on the briefs:* Guy R. Rosenschein, New Mexico, pro se Defendant-Appellant. Alexander M.M. Uballez, United States Attorney, and Tiffany L. Walters, Assistant United States Attorney, Albuquerque, New Mexico, for Plaintiff-Appellee. _________________________________ Before HARTZ, EID, and CARSON, Circuit Judges. _________________________________ EID, Circuit Judge. _________________________________

* After examining the briefs and appellate record, this panel has determined unanimously that oral argument would not materially assist in the determination of this appeal. See Fed. R. App. P. 34(a)(2); 10th Cir. R. 34.1(G). The case is therefore ordered submitted without oral argument. Appellate Case: 23-2017 Document: 164-1 Date Filed: 05/12/2025 Page: 2

In 2016, an anonymous user uploaded images of child pornography to Chatstep, an internet chatroom service. Using a Microsoft product called PhotoDNA, Chatstep identified and reported the uploads to the National Center for Missing & Exploited Children (“NCMEC”). Based on location data derived from the IP address accompanying the files, NCMEC forwarded the reports to the Bernalillo County Sheriff’s Office (“BCSO”) in New Mexico. BCSO investigated the reports, identified the user as Guy Rosenschein, and obtained a warrant to search Rosenschein’s home in Albuquerque. The search uncovered approximately 21,000 images and videos of child pornography on electronic devices in Rosenschein’s possession.

A grand jury indicted Rosenschein on charges of possession and distribution of child pornography, in violation of 18 U.S.C. §§ 2252A(a)(2), 2252A(a)(5)(B), 2252A(b)(1), and 2256. Rosenschein filed three pre-trial motions in response. First, Rosenschein moved to suppress the evidence of his uploads, arguing that Chatstep’s warrantless search of his files through PhotoDNA violated the Fourth Amendment. He also claimed that, as a result of that unlawful search, any evidence of child pornography found in his home should be suppressed under the exclusionary rule. Second, Rosenschein moved to dismiss the case, or, in the alternative, to compel the discovery of the computer programs used by Microsoft and NCMEC to generate reports of child pornography. And third, Rosenschein moved to compel the government to require expert reports for two of its witnesses before the suppression hearing.

2 Appellate Case: 23-2017 Document: 164-1 Date Filed: 05/12/2025 Page: 3

The district court denied each of Rosenschein’s motions. Rosenschein subsequently pleaded guilty to one count of possession of child pornography and seven counts of distribution of child pornography, reserving his right to appeal the district court’s decision to deny his motions.

Exercising jurisdiction under 28 U.S.C. § 1291, we affirm the district court’s denial of all three motions. First, because Chatstep and Microsoft were not acting as governmental agents, the Fourth Amendment does not protect Rosenschein from their conduct. Further, even if Chatstep and Micros