(FILES) This file photo taken on August 20, 2016 shows US Gil Roberts as he celebrates winning the Men's 4x400m Relay Final during the athletics event at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro. Gil Roberts, who won Rio Olympic gold on the US men's 4x400-meter relay, was cleared of doping after an arbitrator found he ingested a banned substance by kissing his girlfriend. According to a final US Anti-Doping Agency (USADA) report in the matter unveiled on July 13, 2017, the ruling that cleared Roberts of wrongdoing turned on his girlfriend, Alex Salazar, having taken medicine for a sinus infection that contained the banned masking agent probenecid. / AFP PHOTO / Adrian DENNIS