Story highlights
- Whistleblower claims champions doped at Sochi
- WADA says allegations "very disturbing"
- Russian athletes already banned from competition
(CNN)It could prove to be the final nail in Russia's Rio Olympic coffin: the World Anti-Doping Agency is to investigate claims that four Russian gold medalists at the 2014 Winter Games in Sochi used steroids.
Russian intelligence agents also "tried to control every single step of the anti-doping process in Sochi," whistleblower Vitaly Stepanov, who used to work for Russia's anti-doping agency, told CBS' "60 Minutes." The program aired Sunday.
IAAF president on Russia's future in athletics 02:05
Stepanov said he has more than 15 hours of taped conversations with Grigory Rodchenkov, the former head of Russia's drug testing laboratory (RUSADA). It's in those conversations Stepanov said, that Rodchenkov mentions the four athletes and their alleged steroid use.
CNN was unable to independently confirm the information in the "60 Minutes" report, while the Russian Sports Ministry and the country's Olympic Committee did not respond to requests for comment.
"The claims made in the program offer real cause for concern, as they contain new allegations regarding attempts to subvert the anti-doping process at the Sochi Games," WADA president Sir Craig Reedie said in released statement.
"Mr. Rodchenkov was of course interviewed by WADA's Independent Commission that exposed widespread doping in Russian athletics last year; yet, regrettably, he was not forthcoming with such information related to the Sochi Games.
"It is surprising to hear these views so many months after the Commission concluded its work," added Reedie.
Russia's former anti-doping chief found dead 01:21
Stepanov and wife Yuliya, a former elite runner who has admitted steroid use, now live in hiding after lifting the lid on Russian doping.
Russia was banned from all Olympic track and field events indefinitely, including the Rio games in August, after a WADA report said the country effectively ran a state-sponsored doping program.
Its athletes will only be allowed to return when Russia can prove it has overhauled its drug-testing program.
Russian sports minister Vitaly Mutko told the state-owned news agency TASS that: "The CBS film was purposely aired ahead of the meeting of WADA directors and founders. Nothing is done just like that." The meeting begins later this week.
Travis Tygart, the chief executive of the U.S. Anti-Doping Agency, told CBS it was a "stunning revelation," and if true a "devastating blow to the Olympic values."
CNN visits secretive Russian lab 02:40
