Duke said it found no proof that Williamson, the 2019 ACC Player of the Year as a freshman and the No. 1 pick by the New Orleans Pelicans in June's NBA draft, received improper benefits that would have made him ineligible to play for the Blue Devils last season.
"As soon as Duke was made aware of any allegation that might have affected Zion Williamson's eligibility, we conducted a thorough and objective investigation which was directed by individuals outside the athletics department," Duke spokesman Michael Schoenfeld told the News & Observer, which was first to report results of the investigation. "We found no evidence to support any allegation. Zion thrived as both a student and an athlete at Duke, and always conducted himself with integrity and purpose."
In a statement to ESPN on Friday, Avenatti said the people conducting Duke's outside investigation never contacted him.
"I never heard from anyone associated with Duke in connection with my allegations or any investigation," Avenatti said. "I was never asked a single question. I was never asked what information or documents that I was aware of. Who the hell conducted this investigation? Inspector Clouseau?
"The documents and the hard evidence do not lie. Zion Williamson was paid to attend Duke. [Coach Mike Krzyzewski] has made and facilitated payments to players for years. And when the truth comes out -- and eventually it will -- Coach K and Duke's reputation will forever and rightfully be tarnished.
"And if what I'm saying is untrue, I challenge Coach K and Duke University to file a defamation lawsuit against me tomorrow and we can let the chips fall where they may."
Last month, Avenatti's attorneys filed a court motion that alleged a Nike employee at least approved under-the-table payments to Williamson and former Indiana star Romeo Langford when they were still in high school in February 2017.
The alleged offers -- $35,000 or more for Williamson and $20,000 for Langford -- were purportedly discovered among "text messages, e-mails and other documents from 2016-17 ... proving that Nike executives had arranged for and concealed payments, often in cash, to amateur basketball players and their families and 'handlers,'" according to the motion filed in U.S. District Court in New York.
Federal prosecutors charged Avenatti in March with attempting to extort up to $25 million from Nike by threatening to expose the shoe company's alleged improper payments to high-profile players in its grassroots basketball league, the EYBL.
Avenatti has pleaded not guilty, and last month his lawyers asked a federal judge to dismiss the charges on grounds of vindictive and selective prosecution.
The dates to mark off on the Zion debut tour
The hype surrounding Zion Williamson has seldom been seen, and Scoop Jackson lists the important dates for when Williamson and the Pelicans hit the road.