Olympics: The thrill and the agony

"I think that is a sign that the system works," Rogge said Sunday. "I am happy about the fact that we could catch athletes who cheated, both before the games and at the games."

The IOC had said this would be its most extensive Olympic anti-doping program. It took almost 6,000 urine and blood samples, including no-notice tests ahead of athletes competing.

Rogge cautioned that some samples are still being analyzed and "we might hear something tomorrow or the day after. Hopefully not, but you never know."

Syrian runner Ghfran Almouhamad tested positive for the stimulant methylhexaneamine two days before her 400-meter hurdles heat. She placed eighth and was eliminated before the IOC disqualified her.

Until this latest turn of events, the London Games were set to end with medal standings in all 302 events unaltered by doping scandals.

Three Beijing events were tainted during the games, and two more medals were changed months later when a new test for the blood-booster CERA was introduced. The signature men's 1,500-meter gold medal was stripped from Rashid Ramzi of Bahrain.

Rogge reminded that the IOC will store all samples from London and can reanalyze them, revise results and reallocate medals until the statute of limitations expires in August 2020.

"When there is no new tests, we wait until the last moment; if there is a breakthrough new test, we'll test immediately," he said.

Indeed, the next Olympic doping scandal could be from the 2004 Athens Games instead. Next week the IOC could announce up to five new disciplinary cases based on retested samples.