Last week on the Diane Rehm Show (on NPR) I heard a couple of authors who have new Kennedy assassination books out.  I don't have their names or their book titles but one of them mentioned having a long suppressed letter to a government agency in which Oswald is quoted as saying that he intends to assassinate Kennedy.  Anyone know anything more about this?

Also, one of the authors asserts that the real cover-up involved the CIA and FBI trying to hide their own gross negligence.  He more or less claimed that both agencies knew enough about Oswald to have kept closer tabs on him and probably have stopped the assassination.  But his main point seemed to be that there was a cover-up to keep other operations they were involved in from  being exposed to public scrutiny.