🚨The FBI was asked about having information on who Satoshi Nakamoto is, and their response was:
"We cannot confirm or deny the existence of records about third parties due to privacy exceptions, and as a result, the request was closed."
Discussion
Of course they know who he is. But this is probably just a standard form letter they would send if you asked about anyone outside the FBI.
They don't know, and even if they did, they could only prove someone is Satoshi if that person signed. There are several indications that it could be Nick Szabo, but there's no way to prove it.
3rd Party “Individuals”