Two men charged for threatening USADA CEO Travis Tygart

Since then, Armstrong has admitted to doping and stepped down from the Livestrong Foundation, which raised hundreds of millions of dollars for cancer research

Travis Tygart made international headlines in pursuing doping allegations against Lance Armstrong :: John Thys/Getty Images

Since then, Armstrong has admitted to doping and stepped down from the Livestrong Foundation, which raised hundreds of millions of dollars for cancer research based largely on the cyclist's popularity. Armstrong overcame testicular cancer before winning his first Tour de France and used his story as an inspiration for others battling cancer.