Ok, so here is a FBI Vault update:

I read all 4 files on Adolf Hitler. There are several things going on. First, the overarching theme is that the FBI thinks, most like but not definitively, that Hitler is alive and is investing time and resources into actively looking for him. The most likely location is South America. Second, there are 2 reports that they take as credible, as evidenced by the subsequent memos, that Hitler had been in the USA. Third, he probably came to the USA to attend Bund meetings, among other activities. The German-American Bund, which was officially broken up by law once Germany/Hitler became Enemies of the State, most likely remained underground as seen in the separate Bund files, and would have provided a Network within which Hitler could move clandestinely through USA. Fourth, this could be a Red Herring because there is at least 1 letter that is clearly disinfo sent to the FBI. I believe it is disinfo, not because of the actual content of the letter but, because of the sender. It is a known individual to the FBI, but some detail in the subsequent memo - such as a group association or something - made me suspicious of the author of the letter. There are other details in the files, but those are my big takeaways and suggest everyone read the files. They are fascinating and make for good bedtime reading.