I agree that would seem out of character, but that brings me back to the other ethical issue.
If he is certain, then someone has apparently given him information that the DA, himself, said, is of a nature that should not be disseminated.
Believe what you will, but I will be very surprised if this thing ever sees the light of day. Of course Bill O'Reilly will never come back and say there was no 'there" there.
If it is shown to be undeniably true, we who have maintained serious doubt of guilt will probably have our minds changed.
Until such time as I see true evidence of a confession, I will stick with my current belief.