One of the world's best known athletics coaches, Alberto Salazar is at the centre of doping allegations. According to a BBC investigation, Salazar has been accused of violating anti-doping rules, including claims he was involved in doping US record holder Galen Rupp, in 2002.Rupp and GB Olympic gold medallist Mo Farah are part of Salazar's US stable, the Nike Oregon Project. There is no suggestion Farah has broken any rules. Salazar and Rupp deny any wrongdoing.