They may not have known her name, but they knew it was the same person who drove Mangum to Kroger's. It's in the dispatch tapes.
If Nifong lied, he lied to more than Abrams. He said on National TV many times that the ID of the first 911 caller was unknown.
The Police spokesman made offical statements and ads were placed asking for the individual to come forward.
This is serious because so much is on record in this case. Nifong was asked point blank: Do you know the Identity of the first 911 caller? He said, NO.
There's not much wiggle room there.