All of that, if you look at the restraining order documents, is what Kaine's attorney alleges LE told her. Some of the info LE in turn alleges that Cook told him. In other words, it is not all firsthand info. There is documentation that shows the pictures on Cook's cell phone, for example, but how it got there, what Terri said and did, was simply verbally, whisper-down-the-lane style - from Cook to LE to Kaine's attorney.
It could be that Cook admitted that the way he originally told LE it happened was not in fact the way it happened. For example, it could have turned out that he admitted that he saw the documents lying on a table, Terri not even in the room, and that he took the pictures, and gave the info to the two persons he did. Something like that may account for why this is being dropped.