Olympic chiefs have announced 23 competitors at the London 2012 Games have failed retrospective doping tests. Those athletes are from five different sports and six different countries. The International Olympic Committee re-tested 454 selected doping samples from the 2008 Games in Beijing and a further 265 from London 2012. It said, the retests conducted using the latest scientific methods, were focused on athletes who could take part at this year's Rio Olympics. IOC President Thomas Bach today said, these re-analyses show, once again, their determination in the fight against doping. He said, we want to keep the dopers away from the Olympic Games in Rio de Janeiro. Last week, the IOC announced 31 athletes from the 2008 Games had tested positive following re-examination of their samples.