LAUSANNE, Switzerland -- Tyler Hamilton turned over his 2004 cycling gold medal to the United States Anti-Doping Agency on Friday, putting Russian Viatcheslav Ekimov in line for an upgrade from silver.
The International Olympic Committee had said it could strip Hamilton of his time trial gold at the Athens Olympics after he told CBS' "60 Minutes" he doped and said Lance Armstrong did as well. But USADA released a statement Friday saying Hamilton had already handed over the medal.
"USADA continues its ongoing investigation into the sport of cycling,'' USADA CEO Travis Tygart said in an emailed statement. "Where there is credible evidence of doping, a fair and thorough process exists for resolving such violations. We do not comment on the substance of an active investigation, but as always we remain committed to protecting the rights of clean athletes and preserving the integrity of sport."
Tygart added: "As stated by the IOC, I can confirm that Tyler Hamilton has given his gold medal from the 2004 Athens Olympic Games to USADA and that we will continue to work with the IOC and the USOC as appropriate concerning the final implications of our overall investigation."
The IOC can retroactively strip Olympic medals if proof of doping emerges later or an athlete admits to cheating. The IOC took away Marion Jones' five medals from the 2000 Sydney Games after she admitted using performance-enhancing drugs.
The IOC had provisionally investigated Hamilton for doping after he won in 2004. An initial test at the Athens Games suggested the American had received an endurance-boosting blood transfusion. But the case was dropped after his backup sample was mistakenly frozen, leaving too few red blood cells to analyze.
In the interview with "60 Minutes," which will be aired more extensively Sunday, Hamilton said that he saw Armstrong use performance-enhancing drugs, including the banned blood-booster erythropoietin, in 1999 and two subsequent seasons to help prepare for the Tour de France.
"I saw (EPO) in his refrigerator .. I saw him inject it more than one time like we all did, like I did many, many times," Hamilton told Scott Pelley of "60 Minutes." "(Armstrong) took what we all took ... the majority of the peloton. There was EPO ... testosterone ... a blood transfusion."
"20+ year career. 500 drug controls worldwide, in and out of competition. Never a failed test. I rest my case," Armstrong tweeted Thursday night.
Armstrong told The Daily Beast website Friday that "60 Minutes" "basically reneged" on promises made to him, saying he "would not call (the '60 Minutes' producer) a straight shooter."
CBS News chairman Jeff Fager, who is also executive producer of "60 Minutes," told The Daily Beast: "We have been so thorough and fair to Lance Armstrong."
Fager added: "We have shared with them every single allegation in our story ... This is a PR game. Our reporters have done a first-class job."
Hamilton, 40, wrote and sent a letter Thursday -- also provided to ESPN.com -- to his close friends and family in what he called a "long overdue" confession, admitting to his own doping history after years of vigorous denials.
"During my cycling career, I knowingly broke the rules," Hamilton wrote. "I used performance-enhancing drugs. I lied about it, over and over. Worst of all, I hurt people I care about. And while there are reasons for what I did -- reasons I hope you'll understand better after watching ('60 Minutes') -- it doesn't excuse the fact that I did it all, and there's no way on earth to undo it."
Hamilton, who retired in April 2009 after announcing he had knowingly committed a second doping offense, had previously described his own and his famous teammate's alleged doping in six hours of closed-door testimony before a federal grand jury after being subpoenaed last July.
Hamilton told his family and friends in the letter that testifying before the grand jury felt like "the Hoover Dam breaking." In addition to clearing his own conscience, he said he elected to be interviewed by "60 Minutes" because he hopes it will help bring long-term change to a sport plagued by scandal, dishonesty and corruption.
Also Friday, two former Armstrong teammates told The Associated Press that they never saw Armstrong or Hamilton use banned substances. But Pascal Derame, a Frenchman who was on the 1999 Tour-winning team with Armstrong and Hamilton, said he wasn't in Armstrong's "inner circle."
"I never saw (Armstrong) take anything," Derame said. "I cannot say what I didn't see."
Another former teammate of Armstrong and Hamilton, Steffen Kjaergaard of Norway, rode on U.S. Postal's Tour de France team in 2000 and 2001.
"I didn't feel any pressure of doing any prohibited thing to be stronger, to do doping," Kjaergaard said. "I didn't have any hints, 'You should do this. You should do that.'"
The Russian Olympic Committee failed in a 2006 appeal to the Court of Arbitration for Sport to have Hamilton's gold given to Ekimov, Hamilton's former U.S. Postal Service teammate.
Ekimov, a longtime member of Armstrong's U.S. Postal and Discovery Channel teams, already has two Olympic golds. He won in track team pursuit at the 1988 Seoul Olympics, when the Soviet Union edged East Germany for gold. At the 2000 Sydney Olympics, he won the road time trial ahead of silver medalist Jan Ullrich and Armstrong in third for bronze.
Armstrong posted a message for Ekimov on his Twitter page late Thursday.
"Congratulations to @eki-ekimov on his 3rd Olympic Gold Medal!!" the seven-time Tour de France champion wrote.
Information from The Associated Press and ESPN.com's Bonnie D. Ford is included in this report.