Jezebelle has really hit upon something here.
Nifong is used to forcing defendants by leveraging, bullying, and just plain overpowering them. Nifong's modus operandi is to shift the evidence to match his theorizes and that's incredibly successful against Durham Defendants - day in and day out. HOWEVER, in this case .. the Media showed up with Cameras and people - ON CAMERA - provided their story in detail (like Bissey). This throws a wrench in Nifong's Standard Operating Procedure.
It's VERY easy for authorities to make someone feel uncertain about a portion of their story - make them think there's conflicting evidence (the police know more and are just confirming your statement). Through outright suggestion, facial expressions, and specifically focusing on one facet of their story, investigators get witnesses to shift their story. Investigators then provide positive reenforcement (verbal or non-verbal) to the witness and the now you have corroborating of the state's theory.
Nifong is playing on a different field now. The Media has eyewitness statements on Camera before the police had them sign affadavits to a story that fits the accuser's story.