“Meredith told me she had been raped twice at Duke,” Mr. Jones said. “And she told me that one of the men who raped her was the Duke basketball player Corey Maggette. That was a name I knew because I’m a basketball fan.”

Mr. Jones, who did not attend Duke, said he had not had much contact with Ms. Watson in the last decade “other than occasionally liking a Facebook post.” He said he was coming forward now because it “seemed like the right thing to do.”

The longtime coach of Duke’s men’s basketball team, Mike Krzyzewski, said after his team’s victory against Virginia on Saturday night that he had “no knowledge” of the situation and that he had learned of it only from news media reports Friday.

Karen Kessler, a spokeswoman for Ms. Watson, provided The New York Times with a Facebook message exchange between Ms. Watson and a friend from March 2017. Ms. Kessler declined to identify the friend, whose name was blacked out in the messages, and The Times was unable to independently verify the authenticity of the messages.

In the messages, Ms. Watson expressed disgust at a newspaper article written about Mr. Fairfax, who had already announced his bid for lieutenant governor. After the friend asked Ms. Watson whether she had reported the rape, Ms. Watson responded: “You know I didn’t report it after how the university responded when I reported Corey Maggette.”

Ms. Kessler said that after being discouraged by the dean, Ms. Watson decided not to report her accusation to the police.

Mr. Krzyzewski — who is in his 39th season coaching the Blue Devils and is college basketball’s leader in wins — and Duke have held themselves up not only as consummate winners but as moral exemplars.

No Duke player under Mr. Krzyzewski was kicked off the team until early 2015, when a player was dismissed for unspecified struggles to meet “necessary obligations.” The university’s student newspaper, The Duke Chronicle, reported that the player, Rasheed Sulaimon, had been accused of sexual assault by two students, allegations the athletics department had been aware of as early as 10 months before terminating his participation with the team. (Sulaimon was not charged, and later played for Maryland.)