Rogge and Ioc to Investigate Jones

Marion Jones was under growing pressure last night after the International Olympic Committee president Jacques Rogge set up an investigation into allegations she used banned performance-enhancing drugs. The American could be stripped of the five medals, three of them gold, that she won in Sydney in 2000.

Rogge has acted over the claims made last week by Victor Conte, the owner of the Bay Area Laboratory Co-operative, on television and in a magazine that he provided her with a cocktail of illegal substances during the run-up to Sydney. The sprinter has repeatedly denied using banned drugs and has threatened to sue Conte.

"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.

Rogge advocates a "zero tolerance" policy on doping. "I hope the truth will emerge," he said. "We want the truth. We want to know what happened and the more we know the better."

The statement said the disciplinary panel would present a report to the IOC's executive board, which "has the authority to take decisions in relation to the Olympic Games".

Under the IOC charter, Olympic decisions can be challenged within three years of a games' closing ceremony. The Sydney Olympics ended more than four years ago, on October 1, 2000. But Dick Pound, the chairman of the World Anti-Doping Agency, said that rule might 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," he said. "It's arguable there was no decision taken, just a list of results. So you're not challenging a decision."