An "Eyewitness" for the Prosecution

Who could this eyewitness to the David/Crow/Rove smackdown possibly be?

In the eyewitness' version, again, David and Crow are a bit more aggressive than their own story suggests. The eyewitness says David told Rove, You need to bring in new people to tell you the truth. Rove mentioned Dr. John Marburger, the White House science advisor. At that point, according to the eyewitness, Crow began poking Rove's chest with her finger, demanding to know what corporations were underwriting Marburger's work. Rove said Marburger had been in academia most of his career.

I'm told that people just a few feet away couldn't hear what the participants were saying, but maybe there was a really good lip-reader around...