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 (IOC) retested 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.
London 2012 Olympics: 23 competitors return positive drug tests
