Jamaican sprinter Nesta Carter has been named in reports as one of the athletes who retrospectively failed a drug test at the Beijing Olympics in 2008.
The Jamaica Gleaner newspaper reported the 30-year-old, a two-time Olympic gold medallist in the 4x100 metres relay, returned a positive test for the banned stimulant methylhexanamine when his 'A' sample was retested.
The news, if confirmed, could have major implications for Usain Bolt, who, as a team-mate for Carter, could be in danger of losing his relay gold from Beijing.
The International Olympic Committee retested 454 samples from the Beijing Games, with 31 testing positive.
Carter also won relay gold at the 2011, 2013 and 2015 World Championships, all alongside Bolt.