WASHINGTON — After a Kansas man was convicted of possessing and sending child pornography, he appealed to the United States Court of Appeals for the 10th Circuit. The case came before a three-judge panel that included Judge Neil M. Gorsuch, who is now President Trump’s Supreme Court nominee.

The Kansas man had been caught because an AOL system that scans outgoing emails for known images of child pornography detected such a file attached to a message he had sent. The AOL system forwarded the email to the National Center for Missing and Exploited Children, which opened it without a warrant and alerted law enforcement officials.

Citing the Fourth Amendment, Judge Gorsuch’s panel overturned his conviction last August.

Writing for the panel, the judge expressed confidence that in the future, the center’s “law enforcement partners will struggle not at all to obtain warrants to open emails when the facts in hand suggest, as they surely did here, that a crime against a child has taken place.” (He also left open the possibility of reinstating the evidence against the Kansas man after further proceedings.)