BTW, how do we know she hasn't come clean with the cops?
Because Mark Hulbert hasn't had the samples tested; guess he was afraid to find out just how many guys she's been with.
Your question contains some unfortunate phrasing.
If she had, it's likely the DA would have realized that he has no case, since there is now more than just reasonable doubt introduced into the case.
Rape victims do not typically have sex within hours after their rape.