I've gone back and forth on whether or not Nifong ever believed her, and judging by his continual unethical behavior, I don't think he did.
When this story broke, my gut reaction was that Mangum was a prostitute and the players had consensual sex with her, but did not rape her. I have to believe that Nifong, who knew Mangum was a prostitute, thought the same thing and was confident he was going to find the player's DNA on her, so he ran with the case.
Just consider the reaction of Nancy Grace and Wendy Murphy with NO DNA evidence linking the players to Mangum. If Nifong could have come up with DNA evidence, even if it was tranferred through consensual sex, I have little doubt these boys would be convicted of rape by a Durham jury and the Drive By Media.
to support you post: I remember her defenders saying even a prostitute can be raped when this thing first came out