Duke University said Saturday it is "looking into" allegations made by celebrity lawyer Michael Avenatti that the mother of star freshman Zion Williamson was paid for "consulting services" by Nike. Avenatti, who has been charged by federal prosecutors in New York for allegedly trying to extort Nike for nearly $20 million, claimed on Twitter Friday night that Nike paid Williamson's mother, Sharonda Sampson, for "bogus consulting services" to get Williamson to choose Duke.

"We are aware of the allegation and, as we would with any compliance matter, are looking into it," Duke vice president and director of athletics Kevin White said in a statement. "Duke is fully committed to compliance with all NCAA rules and regulations. Every student-athlete at Duke is reviewed to ensure their eligibility. With regard to men's basketball: all recruits and their families are thoroughly vetted by Duke in collaboration with the NCAA through the Eligibility Center's amateurism certification process."

Sampson has not yet responded to the allegations.

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Avenatti did not offer any proof for these allegations.

CHARLOTTE, NORTH CAROLINA - MARCH 16: Zion Williamson #1 of the Duke Blue Devils reacts against the Florida State Seminoles during the championship game of the 2019 Men's ACC Basketball Tournament at Spectrum Center on March 16, 2019 in Charlotte, North Carolina. SL / Getty Images

Avenatti also alleged Friday night that Nike paid families of other top recruits. Avenatti tweeted out documents -- including what appeared to be redacted bank statements and invoices he says are fake -- he claimed backed up his allegations.

Avenatti alleged a senior executive at Nike "has bribed over 100 high school players over the last four years to play college basketball at colleges affiliated with Nike as opposed to other schools." He further claimed senior executives at Nike and other schools looked other way.

In a statement, Nike said it "will not respond to the allegations of an individual facing federal charges of fraud and extortion and aid in his disgraceful attempts to distract from the athletes on the court at the height of the tournament. Nike will continue its cooperation with the government's investigation into grassroots basketball and the related extortion case."

In March, the U.S. attorney for the Southern District of New York accused Avenatti and another attorney of threatening to release what Avenatti claimed is damaging information about Nike if the company did not meet his demands.

The U.S. attorney in Los Angeles separately said on the same day that Avenatti faced bank and wire fraud charges for allegedly embezzling money from a client and defrauding a bank through fake tax returns.

Avenatti has denied the charges. He told "CBS This Morning" in March that the allegation that he tried extort Nike is "absurd."

"There's legal experts that say I was well within the line as an aggressive attorney. There's many that say that. And the fact of the matter is, this was not extortion," he said. "People make threats all the time in connection with trying to settle a case."

Avenatti was arrested in New York on March 26, and was released on a $300,000 personal recognizance bond and ordered to surrender his passport. He is also required to report any transactions of $5,000 or more to the court, and his travel is restricted.