Actually, there was quite a bit of stuff that was known to be going on by intelligence intercepts.
If someone is spouting off about the evil U.S. actions regarding internment, ask if they have read Magic: The Untold Story of U.S. Intelligence and the Evacuation of Japanese Residents from the West Coast During WW II.
http://www.amazon.com/Magic-Intelligence-Evacuation-Japanese-Residents/dp/0960273611
If they have not, they are talking from complete ignorance about the key reasons behind the event. You may still disagree with internment, but absent this information, anyone mouthing off on the topic is doing so completely unjustifiably.
The book include much source material, including contemporaneous memos and assessments.
Even if Reagan didn’t know the historical information justifying the action, his understanding of liberalism should have clued him in that the push for the apology was a liberal guilt trap. War requires many actions that would be regrettable outside of war. This was just one of them. Any apologizes for the consequences of a war are owed, if by anyone, by the side that started the war. The infamy of which lives on THIS day. Reagan shouldn’t have apologized.