“I can accept being accused, but they have never proven that I’m the ground zero of it.”

The son of the former head of track and field’s world governing body, Diack is at the center of an ever-widening corruption inquiry that reaches across four continents. Prosecutors say he has spent years behind the scenes, greasing hands in the shadowy intersection of sports, politics and business. They claim he was involved in a scheme to cover up failed doping tests and was the conduit for vote-buying in competitions to host major sporting events, including the Olympics.

Millions of dollars in illicit payments have been transferred through accounts controlled by Diack or his associates, according to prosecutors in Brazil and France, which in January 2016 issued an international arrest warrant for him.

His father, Lamine Diack, one of the most powerful men in sports during his 16-year reign as the head of the International Association of Athletics Federations, known as I.A.A.F., has been detained in France since November 2015 over allegations that he accepted bribes for covering up doping violations for Russian athletes.

Most recently, connections to the Diacks led to the arrest of Carlos Arthur Nuzman, the head of Brazil’s Olympic committee, amid suspicions that Rio de Janeiro’s successful bid to stage the 2016 Summer Games was helped by a $2 million payment to the younger Diack, acting as an intermediary for his father, who could be relied upon to secure the votes of the other African members of the International Olympic Committee.

Over nearly three hours at the Pullman Teranga, Diack described all the accusations as being born of racism and jealousy, part of an Anglo-Saxon conspiracy to tarnish the legacy of his father. He also said he believed the case was part of a power game between the World Anti-Doping Agency and the International Olympic Committee.