Background
Law enforcement identified a peer-to-peer filesharing account offering suspected child pornography. Agents matched hash values of files on the account to known child pornography in their library and observed descriptive filenames. The account was linked to Duane Lee Johnsen, a registered sex offender. Agents obtained a warrant and seized fifty-nine devices, later analyzing over one hundred forty thousand images and nine hundred videos depicting child pornography. Johnsen was convicted on multiple counts and sentenced to one hundred sixty-eight months in prison plus lifetime supervised release.
The court’s reasoning
The panel held that a hash match provides a reasonable inference that child pornography is present, satisfying the fair probability standard for probable cause without requiring agents to download and view the suspect files. The court found that law enforcement’s review of publicly shared files did not violate the Fourth Amendment or the Wiretap Act. The panel further ruled that forensic analysis is not a critical stage of prosecution, so the right to counsel did not attach. Finally, the court rejected the selective prosecution claim because Johnsen presented no evidence of differential treatment or an impermissible motive.
A hash match between a suspect’s files and known child pornography amply supports the reasonable inference that such material is present on the suspect’s devices, even if agents have not downloaded and viewed the suspect file.
United States v. Johnsen, 24-6689 (9th Cir. May 26, 2026)
What it means going forward
The decision clarifies that digital hash matching is sufficient for probable cause in child pornography cases and confirms that defendants have no right to counsel during forensic imaging and analysis of seized devices.
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