United States Court of Appeals For the Seventh Circuit ____________________ No. 23-2207 UNITED STATES OF AMERICA, Plaintiff-Appellee, v. WARREN SIEPMAN, Defendant-Appellant. ____________________

Appeal from the United States District Court for the Northern District of Illinois, Eastern Division. No. 18-cr-130 — Harry D. Leinenweber, Judge. ____________________

ARGUED MAY 13, 2024 — DECIDED JULY 11, 2024 ____________________

Before SCUDDER, ST. EVE, and PRYOR, Circuit Judges. ST. EVE, Circuit Judge. On three separate occasions, an au- tomated government software program accessed and down- loaded child pornography from Warren Siepman’s computer over a peer-to-peer file sharing network. The central issue in this appeal is whether that amounts to “transportation” of child pornography under federal law. It does. 2 No. 23-2207

I. Background A. Factual Background In late 2016, Homeland Security Investigations (“HSI”) agents began investigating individuals making child pornog- raphy available to others on the internet over peer-to-peer file sharing networks. Peer-to-peer file sharing programs enable computer users to share and receive electronic files over the internet with a network of others. See United States v. Clarke, 979 F.3d 82, 87 (2d Cir. 2020). The name “peer-to-peer” comes from the network created when two or more computers con- nect directly with each other, without going through a sepa- rate server. See generally Metro-Goldwyn-Mayer Studios Inc. v. Grokster, Ltd., 545 U.S. 913, 919–20 (2005). Users of a peer-to- peer file sharing network can search for files that others have made available, browse files that a specific user has made available, and download files directly from other users. See United States v. Husmann, 765 F.3d 169, 171 (3d Cir. 2014). Us- ers can also make their own files accessible to others, usually by placing them in a designated folder available to the net- work’s users. Id. When one user makes files available to oth- ers, however, those files remain local on the user’s computer until another user accesses and downloads them. Id. HSI agents here used a proprietary peer-to-peer software program called “eMule” that they engineered to search for specific child pornography files others were making available over a peer-to-peer network. The program combed the net- work by querying the unique alphanumeric identifiers (known as “hash-IDs”—essentially, the files’ digital finger- prints) of already-known child pornography files. Once the program identified a known child pornography file that a net- work user had made available, it connected to that user’s No. 23-2207 3 computer and downloaded the entire file. The program’s search and download functions operated without human in- tervention, and it ran constantly on a secure government com- puter in a locked room during the yearslong investigation. Law enforcement monitored its activity several times per day. Using this program, an HSI agent discovered that Warren Siepman made child pornography available to others for download on a peer-to-peer file-sharing network called “Shareaza.” Between October 2016 and March 2017, the pro- gram identified and then downloaded child pornography from an IP address associated with Siepman on three separate occasions. Forensic examination of hard drives later seized from Siepman revealed over one thousand child pornography files and showed that the computer’s user had searched for child pornography on Shareaza. Siepman, in an interview prior to his arrest, also admitted to viewing child pornogra- phy on his computer, using Shareaza to view and dow