Sorry do not have the link - search newsmax perhaps. That he is protected is plain in the language used. One does not need to spell these thing out. You would never find any document to that effect - not ever. Meaning is all in the language and in who is speaking and who is listening.
The plain language of your post only indicates that the reason he was “protected” was because the independantly developed military intelligence could not be shared with the FBI. Lawyers told intel folks “you can’t touch him” in that context. Again, based on what you posted.
If you’re going to make the leap from the obvious to the paranoid, you do have to spell it out if you think you’re going to convince somebody of what you claim.