VANCOUVER, British Columbia — The IOC opened a formal investigation Sunday into a doping case that could lead to the stripping of gold medals from a U.S. women's relay team at the 2004 Athens Olympics.

The International Olympic Committee executive board set up a disciplinary commission into the case of Crystal Cox, who ran in the preliminaries of the winning 4x400 team in Athens.

The U.S. Anti-Doping Agency said late last month that Cox had admitted to using anabolic steroids and accepted a four-year suspension and disqualification of her results from 2001 to 2004.

IOC vice president Thomas Bach said he will lead a three-man panel into the case. Such a process has previously led the IOC to remove national relay teams of medals retroactively — including three U.S. teams from the 2000 Sydney Olympics.

Under international rules, an entire relay team can be disqualified because of the doping of one member, even an alternate. Russia would move from silver to gold in the 2004 relay if the U.S. team were disqualified. Jamaica was third.

Sanya Richards, Dee Dee Trotter, Monique Henderson and Monique Hennegan ran in the Athens final. Moushaumi Robinson joined Cox in the preliminary heat.

"We will start gathering information here," Bach said. "So far we just have a press release (from USADA) and nothing else. We have to get more information."

The case appears more straightforward than the relay cases from Sydney. The International Association of Athletics Federations had no specific rule in place in 2000 for dealing with an entire relay team in the event of doping by one member. By Athens, however, the IAAF had a rule specifying that the entire team should be disqualified and lose medals.

"I will not speculate on the outcome, but the rules of the IAAF concerning relay teams in 2004 are different from those in 2000," Bach said. "After Sydney, the IAAF changed its rules."

Bach said he didn't know yet whether a hearing would be held for Cox.

"We will give her the opportunity one way or the other to be heard, but first of all we have to check the documents to see how far the admission reaches and then we can take it forward," he said.

The IAAF, which determines official results and placings, will deal with the case at its council meeting in Doha, Qatar, in March during the world indoor championships.

The admission by Cox came after an investigation that was triggered by information from the Bay Area Laboratory Co-Operative case.

The IOC and IAAF still are waiting for the results of an appeals case involving U.S. women's relay runners from the 2000 Games.

The United States was stripped of the gold medal in the 4x400 relay and bronze in the 4x100 relay following Marion Jones' admission of doping. Jones returned her medals, but her teammates appealed to the Court of Arbitration for Sport to keep theirs. CAS is due to rule on the case this year.

The IOC also stripped the U.S. men's 4x400 relay team of their Sydney gold after Antonio Pettigrew admitted doping.