NEW YORK (CBSNewYork) — The FBI is investigating allegations of doping by Russian Olympians following an explosive “60 Minutes” report, someone familiar with the probe told CBS News.

On Sunday, “60 Minutes” reported that Grigory Rodchenkov, the former director of the drug testing lab at the 2014 Winter Olympics in Sochi, Russia, claimed in recorded online video conversations that he knew of at least four Russian gold medalists who used performance-enhancing drugs and said his lab covered up their positive test results. Rodchenkov also alleged the FSB Russian intelligence agency was involved in the testing.

The report focused on Yuliya Stepanov, a former elite Russian runner who admitted to doping at the direction of her coaches and team medical staff, and her husband, Vitaly, who worked at Russia’s national anti-doping agency, RUSADA.

Together, the couple decided to expose the systemic doping in Russia’s athletics program. They both lost their jobs and now live in the United States.

“The evidence confirmed what a lot of people have believed over the years. This is not just a few athletes obtaining performance-enhancing drugs. This was a system orchestrated by the sport leaders to ensure that they won at all costs,” said Travis Tygart, CEO of the U.S. Anti-Doping Agency, who has been advising the Stepanovs.

Yuliya secretly recorded video of athletes admitting to taking performance-enhancing drugs, including 800-meter runner Mariya Savinova, who won gold in London in 2012.

“My coach helps to cover up the tests,” Savinova said in the video. “There is no other way to do it. Everyone in Russia is on pharma.”

The Stepanovs’ findings spurred an investigation by the World Anti-Doping Agency. It issued a 300-plus-page report detailing what the agency called a “deeply rooted culture of cheating” that reached the highest levels of the Russian government.

A WADA spokesman said its officials watched the “60 Minutes” report, “which revealed new and very disturbing allegations regarding Russian doping in sport” and vowed to investigate further.

The latest allegations could influence the governing body of track and field when it meets next month to decide whether it should lift a ban on the entire Russian team before the Rio Games begin in August.

The Russian sports ministry said it is “certain” about the transparency of doping controls that were in place during the Sochi Games, adding that its stations employed foreign workers and had independent observers on hand.