Mo Farah's trainer has been accused of violating anti-doping rules.
Alberto Salazar is alleged to have been involved in doping American long-distance runner Galen Rupp in 2002, according to a BBC Panorama documentary that is due to air tonight.
Olympic gold medallist Farah is part of Salazar's stable of athletes, although it is understood that the Brit has not broken any rules.
Salazar and Rupp both deny any wrongdoing.
