In a major doping crackdown stretching back eight years, 31 athletes in six sports were caught in retesting of samples from the 2008 Beijing Olympics, the IOC said today. Other positive cases could emerge from the 2012 London Games, the IOC added. The International Olympic Committee opened disciplinary proceedings against the 31 unidentified athletes from 12 countries who competed in Beijing and were planning to take part in the Rio de Janeiro Games in August. The positive cases emerged from the recent retesting of 454 doping samples from Beijing with "the very latest scientific analysis methods," the IOC said. The Olympic body stores samples for 10 years to allow for retesting with improved techniques. The IOC said it would inform the relevant national Olympic committees in the coming days. The IOC also said that results of retesting of 250 samples from the London Olympics will be announced shortly. Those tests were also aimed at athletes planning to compete in Rio.