Nike Oregon Project coach Alberto Salazar, who oversees the training of several Olympic medalists, is being investigated by the FBI, according to Ben Rumsby of The Telegraph.

The FBI is reportedly working with USADA chief executive Travis Tygart following a leaked report from the anti-doping agency that accused Salazar of “unlawful” conduct. It was previously revealed Salazar conducted an experiment by rubbing testosterone on his own sons to see how much would trigger a positive drugs test. Salazar has denied any wrongdoing and none of his athletes have tested positive for performance enhancing drugs.

The most recent allegations stem from a Sunday Times article that pulled from the leaked USADA report, which was written in March 2016, and stated that Salazar has an “obsession with the testosterone levels of his athletes.” Salazar’s alleged possession of testosterone gel was first revealed in 2015 and he said in an 11,736-word statement at the time that he has a prescription for testosterone to treat hypogonadism.

In USADA's leaked report, it noted: "Mr. Salazar has still produced no laboratory testing records, blood test data, examination notes, chart notes or differential diagnosis substantiating that Mr Salazar suffers from hypogonadism.”

Over the weekend, a report by German Magazine Der Spiegelstated that Salazar did not give up the documents and said they were on the Nike server, which belongs to the sportswear giant. Der Spiegel added that Nike wanted to sign a “confidentiality agreement” with USADA before complying. ​Nike denied impeding in the investigation.

“I voluntarily provided USADA with medical records, including blood test results, documenting that I have suffered from a diagnosed disability for more than 20 years," Salazar has told BBC. “Any insinuation by USADA that I do not suffer from this condition is offensive to me and my treating physicians, and is inexcusable.”

In 2015, Salazar was the subject of a ProPublica and BBC report alleging he pushed the boundaries on doping rules to gain a competitive advantage by encouraging the use of prescription medication and therapeutic use exemptions. He would allegedly push for use of asthma and thyroid medication for performance enhancement. The joint report also included allegations against U.S. Olympic medalist Galen Rupp, who has never tested positive for any performance enhancing drug and denies breaching an anti-doping code.

- Chris Chavez