The real question is why he leaked information and why he didn't just take the information to the grand jury.  I don't really think that any FBI rules could prevent him from disclosing a crime.   He quit the FBI in 1973 anyway.  Was he really afraid for his life?  Was he paranoid?  Did he have a right to be paranoid? 

The larger question is:  what else does he know?  Might this explain any paranoia and just exactly how far the Nixon Administration might have gone to protect itself?

Apparently he has poor memory now, so unless he has already written a book to be published, his secrets might go to the grave.