The alleged victim told multiple contradictory stories, and you chose to believe the one which is does not fit any of the evidence.
2] my hope that one or more of the persons who were present but not involved with that assault would cooperate with the investigation.
They already were cooperating, even volunteering for DNA and polygraph tests. They didn't get lawyers until several days AFTER they knew they were being investigated. It was Nifong who would not hear what they and their attorneys had to say. More fantastic lies.
"What has surprised me is the utter lack of any degree of skepticism," (quoting the DA), on the part of the DA.