This question already has an answer here:
The Japanese Declaration of War against the UK and USA was given on 1941 Dec 7. This happened in Washington DC via the Japanese Embassy.
I would like to know what happened to that embassy and the Japanese diplomats there. Were they arrested and sent to an internment camp? Was the embassy raided for documents and shut down?
I did see this article of Nomura, which says
On August 20, 1942, Nomura returned to Japan. He continued to serve in an unofficial capacity as an advisor to the government through World War II, and was appointed to the Privy Council in May 1945.
However, it is unsourced and does not give details, e.g., was he arrested and spent half a year in an internment camp before being released to Japan? And I'm asking about all the Japanese diplomats at the embassy, not just Nomura.