American athletics authorities covered up a positive drugs test by new world 400m champion Jerome Young in 1999.
Young edged out Tyree Washington in Tuesday's 400m final
Young tested positive for banned drug nandrolone but was allowed to compete in the 2000 Olympics and went on to win a gold medal as part of the 4x400m relay team in Sydney.
USA Track and Field's (USATF) decision to bury the positive test was heavily criticised by the head of the World Anti-Doping Agency (Wada), who called for an investigation into the matter.
Wada boss Dick Pound said USTAF had "engaged in a conspiracy of silence".
Young was one of 13 athletes named by the Los Angeles Times who tested positive for drugs between 1996 and 2000 but whose names were not released by USTAF.
"The legitimacy of the US win in the 1,600m (4x400m) relay in Sydney is now shattered," said Wada president Pound.
"By not reporting the positive result to the IAAF immediately, the USATF engaged in a conspiracy of silence.
"The doping violation by Young was overturned by the USATF and no one else had the opportunity to review the case.
"I believe that the IOC must act decisively in this matter to preserve the ethical values of Olympic sport and the image of the Olympic Games."
Young competed in the early rounds of the 4x400m relay in Sydney and was one of the team members awarded a gold medal.