JIM SCIUTTO (HOST): Perhaps our viewers may not know why. But why would [former FBI director James Comey] take such detailed notes of a meeting like this with the president?
WALTER MACK: Well, in many respects, I share with him the same training that every former assistant U.S. attorney has, which is you never want to be in a situation where you do not have a witness to a conversation with a subject target or anyone else. And if, by some means, you are required, and you can't bring somebody, an aide or a confidante or an agent or a detective, you are trained to immediately, after the meeting, sit down and to the very best of your ability write up in some type of a report exactly what happened.
SCIUTTO: Write it and share it apparently with others. Is that --
MACK: Absolutely. Share it. It becomes part of the case file and is information accessible to all of those who are going to evaluate it.
SCIUTTO: Now, you've heard Republicans, a familiar talking point in the last 24 hours has been well, if he was so concerned about the meeting, why didn't he immediately share the contents of this memo?
MACK: Well, I think that's a judgment call that you have to give the benefit of the doubt to Jim Comey because as I -- and I read the press. I'm a newspaper news person. And I think his position was that he had a group of hard-working agents and assessors, evaluators working on it and if, in fact, the memo says what, in fact, it's purported to say, this would indelibly impact the brains of those investigators working on the case. It might cause them to react in a negative way.
