In answer to your questions: Once a Prosecutor (Special or not) has zeroed in on a particular individual, he sends a letter on that. Otherwise, if that individual was called as a witness without the warning, that could jeopardize the entire case. For example, Ollie North and Admiral Poindexter whose charges were ultimately dismissed in Iran-Contra.
As for the wheels within wheels on who is saying what in this investigation, it is entirely beyond control on the various leaks of who said what. Nobody is in control of this.
Congressman Billybob
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