For years, Anon-IB, the internet’s most notorious epicenter of revenge porn, thrived as users posted nude photos and videos of women without their consent. They published these images under the assumption that they were anonymous—their usernames were “Anonymous” followed by a string of letters.

A new heatmap visualization using IP adresses of Anon-IB users highlights that people who share revenge porn on the forum weren’t as anonymous as they may have thought.

In March, cybercrime teams from the Dutch police seized the Anon-IB forum as part of an investigation. Einar Otto Stangvik, a Norwegian security analyst, turned the IP address data—strings of numbers that reveal the location of a computer connected to the internet—that he collected before the seizure, into a heat map of where people were posting from.

Stangvik shared much of the data, which spans from February 2015 to January 2018, with The Daily Beast in January.

Across the months and years, hotspots on the map fluctuate, but the IP addresses stay clustered mostly along the east coast of the US, the UK, and Germany. In Stangvik’s findings a significant portion of the posts were coming from Senate, Navy bases, and Executive Branch computers.