U.S. Anti-Doping Agency

After new revelations, WADA to probe claims of Sochi doping

The World-Anti Doping Agency is expanding its investigation into doping inside the Russian sports system after a whistleblower alleged four of the country's gold medalists from the Sochi Olympics were on steroids.

WADA announced the long-called-for expansion of the probe Tuesday, two days after Vitaly Stepanov told CBS' "60 Minutes" that he had conversations with the former director of the Moscow anti-doping lab, who told him there was a "Sochi List" that included four champions from the 2014 Games.

"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...