I remember that on one of my visits there (there was always a hard-drive that needed to be handed in person or something like that) I’m 100% sure that I had bumped into what looked to be an FBI team inspecting some of the machines in there. I’m saying FBI but they could also have been the the US Secret Service or whatever agency is in charge with protecting US citizens against online bad things, in any case, the people I saw inspecting stuff were definetely people working for the US government, you could tell by their pants and the way they matched (or, better yet, how they didn’t match) with their white snickers.
All this to say that I’m pretty sure that the US 3-letter agencies had direct physical access to the 8chan servers, not sure how they let all this get so out of control.