Lance Armstrong’s ex-teammate Tyler Hamilton says he saw his former U.S. Postal Service teammate use the performance-enhancing drug EPO “many, many times” in order to win the Tour de France. Hamilton made the allegations during an interview with 60 Minutes, which will air on Sunday, and accused him specifically of using the drugs during the 1999 Tour de France and to prepare for the Tours in 2000 and 2001. Hamilton has himself been sanctioned twice for doping, and is the second of Armstrong’s teammates to accuse him of using performance drugs — Floyd Landis, who was in 2006 stripped of the Tour de France title for doping, also said Armstrong was part of a systematic doping scheme. Armstrong took to Twitter to deny the allegations: “20+ year career. 500 drug controls worldwide, in and out of competition. Never a failed test. I rest my case.”