This is really quite good. (A few nitpicks: it's very atmospheric to have everything in typewritten or handwritten images, but it's a little frustrating when you have to retype an entire Caesar-shifted message instead of being able to copy it as text. And at least one of the typewritten notes was spaced to be left-and-right justified rather than having a ragged right margin; not really typewriter-esque, and also made it harder to count the number of letters in the redacted name.)
If this is your first game, I look forward to seeing what else you come up with!