(CNN) -- The only criminal charge to come out of the academic fraud scandal at the University of North Carolina has been dropped.
Orange County District Attorney Jim Woodall announced on Thursday that ex-professor Julius Nyang'oro would no longer be facing a felony fraud charge. He was accused of taking money to teach classes that didn't exist.
Woodall said the decision was based on Nyang'oro's cooperation, both with the criminal investigation, which is over, and the university-sanctioned investigation being done by former federal prosecutor Ken Wainstein.
Wainstein was hired this year by UNC to do another internal investigation, since past investigations pinning the sole blame on Nyang'oro have not satisfied questions and curiosity from the community and from critics of UNC who think the scope of the fake classes was much bigger than UNC admits.
The so called "paper classes" scandal involves hundreds of classes that never met and required little work, and even though many athletes were enrolled in them, UNC and the NCAA have been criticized for saying the issue had nothing to do with athletics.
That all makes the cooperation of Nyang'oro a game-changer in the quest to find answers, and Woodall said last week that is the reason he had been considering dropping the charges.
He said he felt it was better for the community to understand who else knew about the fake classes and who created them than it was for one professor to be punished criminally.
"Even though it's a noncriminal investigation, that is more important than this," Woodall said, referring to Wainstein's review.
Nyang'oro's cooperation also led to the NCAA announcing it would reopen its investigation into academic fraud at UNC. It previously had found no athletic scandal.
But in the last few months, a flurry of reporting has called that into question. Several athletes have said they were pushed into the fake classes by athletic advisers, and whistle-blower Mary Willingham has said that many star athletes were kept eligible by taking the classes.
"That's not just Julius Nyang'oro," Willingham said. "It's what we, the university, used to keep athletes eligible and that just is the truth." Willingham was a UNC employee who told reporters about the classes. She has since quit her job and filed suit against the university.
Wainstein said Nyang'oro's cooperation has been very valuable.
"He has answered all of our questions regarding the academic and athletic dimensions of the irregular courses offered in the department of African and Afro-American Studies, and he has provided important insights and information we would otherwise not have received," Wainstein said.
Wainstein said last week that his team has so far collected 1.5 million e-mails and documents, talked to 30 people in the athletic-academic areas of UNC and is looking at athlete transcripts going back to the 1980s.
That's something no other UNC investigation had done.
"UNC is the mother of all academic fraud violations," said Gerald Gurney, president of the Drake Group for Academic Integrity in College Sport. "...Theres no doubt in my mind about cooperation of friendly faculty and the cover-up and the excuses of this kind of behavior that has gone on in the university. ... It's egregious.
"It's quite likely that if it is shown that this is a long-term systematic scheme on the part of the university that UNC will need to vacate wins," Gurney said.