The International Olympic Committee is launching an investigation into the latest doping charges against sprinter Marion Jones.
It's a step that could lead to invalidating the five medals she won at the 2000 Games.
The head of a California lab that's allegedly provided top athletes with performance-enhancing drugs has said publicly he watched Jones inject herself with human growth hormone.
Victor Conte, head of the California-based lab that allegedly provided drugs to elite athletes, told ABC's "20/20" that he gave Jones performance-enhancing drugs before and after the Sydney Olympics. He said he watched as she injected herself with human growth hormone.
"The allegations made by Mr. Conte are extremely serious and the IOC is fully committed to bringing to light any elements that will help the truth prevail," the IOC said in a statement.
Jones won three gold and two bronze track and field medals in Sydney. She repeatedly has denied ever using banned drugs, and has threatened to sue Conte for defamation.
World Anti-Doping Agency chief Dick Pound, a senior IOC member, has said Jones' medals should be stripped if Conte is telling the truth.
Any decision on the medals would be taken by the IOC executive board.
Under the IOC charter, Olympic decisions can be challenged within three years of the games' closing ceremony. The Sydney Olympics ended more than four years ago, on Oct. 1, 2000.
But Pound said that rule may not apply, because there was no actual decision in this case and the allegations are only coming out now.
"We will find a way to deal with that," Pound said. "It's arguable there was no decision taken, just a list of results. So you're not challenging a decision."
Jones, who did not win any medals at the Athens Olympics, has been under investigation for months by the U.S. Anti-Doping Agency, but has not been charged. USADA has said it will take Conte's allegations into account.
Conte, head of the BALCO lab, said he worked with Jones from August 2000 to September 2001. He said he designed a doping regimen for her that included the previously undetectable steroid THG, the endurance-enhancing hormone EPO, human growth hormone and insulin.
The BALCO lab is at the center of a doping scandal centering on Major League Baseball players Jason Giambi and Barry Bonds.
U.S. Surgeon General Richard Carmona has called for other pro sports to examine whether their athletes are abusing steroids.
"From my standpoint, it is less a moral or ethical issue than it is a public health issue," he said. "If youngsters are seeing their role models practicing this kind of behavior and it seems acceptable, then we need to do something about that because it is a health risk."