Dan who??
Someone please refresh my memory about the letter.
Was it the original letter? If so it was typed on a typewriter. As a college student in the fall of 1969, I was part of a group of college students that visited FBI Headquarters. The agent giving us the tour told us that the FBI had at that time every make and model of typewriter produced. Certainly, Dan and company could have compared the letter with a typewriter in FBI storage and proved the case against George W. Bush.