https://www.vice.com/en_us/article/z34dx3/fbi-wont-say-hacked-dark-web-isis-site-nit

U.S. government lawyers are hampering efforts that could reveal how the FBI managed to obtain the real IP address of an alleged visitor to an ISIS website on the dark web, according to court records reviewed by Motherboard.

The case involves Muhammed Momtaz Al-Azhari, who was charged in May 2020 with attempting to provide material support to ISIS. According to the complaint against him, Al-Azhari allegedly visited a dark web site that hosts “unofficial propaganda and photographs related to ISIS” multiple times on May 14, 2019. In virtue of being a dark web site—that is, one hosted on the Tor anonymity network—it should have been difficult for the site owner’s or a third party to determine the real IP address of any of the site’s visitors.