Any athletes who thought they got away with doping at the Beijing Olympics shouldn't rest easy. The drug police are coming back.

The International Olympic Committee said yesterday it will retest samples from the games to search for a new blood-boosting drug at the center of the latest Tour de France scandals.

The move reflects the IOC's aggressive attempts to nab drug cheats not just during an Olympics, but weeks, months and even years later once new tests become available. Results and medals could be at stake.

"Our message is very clear," IOC president Jacques Rogge said in a statement. "The IOC will not miss any opportunity to further analyze samples retroactively. We hope that this will work as a strong deterrent and make athletes think twice before cheating."

The Beijing samples will be reopened and tested in particular for CERA, a new generation of the endurance-enhancing hormone EPO. The substance boosts an athlete's performance by increasing the number of oxygen-rich blood cells.

No test for CERA was available during the Beijing Games. But a new blood test developed by the French Anti-Doping Agency has since detected CERA in samples of Tour de France riders, and the IOC now wants to go back and check whether it was also used in Beijing.

The IOC has shown increasing willingness to retroactively punish doping cheats. U.S. athlete Marion Jones had to return her five medals from the 2000 Sydney Olympics after she admitted in federal court last year that she had been doping.

In the months before the Beijing Games, the IOC, the World Anti-Doping Agency and international federations carried out a rigorous program of out-of-competiton testing to weed out drug cheats. More than 40 athletes were caught and kept out of the games.

Past doping scandals involving track stars such as Jones raised suspicions heading into Beijing. Even 41-year-old swimmer Dara Torres, who went on to win three silver medals in China, admitted beforehand that past cheating by some athletes had contributed to cynicism about the games.

But no doping scandals involving the biggest-name Olympians emerged in Beijing, despite the suspicion and more than 5,000 drug tests by the IOC, including nearly 1,000 blood screenings.