I don't believe that the allegations that she made, multiple attacks by multiple people, would leave no signs of DNA. And there was no sign of any evidence that a male was present anywhere near that women that day.
I can't comment on the grand jury proceedings. I'm still confident that all the members of the team will be acquitted in the end.
Go back in any news archive and look at the men who have been freed from prison, look at the men that have been taken off death row. Mistakes happen. Bad directions are taken by district attorneys; police make mistakes. It happens all the time: False accusation is commonplace.