Yesterday (September 13), hackers from Russia whom the World Anti-Doping Agency identified as “Fancy Bear” in an online statement broke into the agency’s database to reveal private information about Olympic champion Simone Biles, tennis stars Serena and Venus Williams and basketball player Elena Delle Donne. The act was possibly committed by the same group that helped leak Democratic National Committee emails in July.

Photos by Clive Brunskill and Alex Livesey via Getty Simone Biles, left, and Serena and Venus Williams, right. Photos by Clive Brunskill and Alex Livesey via GettySimone Biles, left, and Serena and Venus Williams, right. (Photos by Clive Brunskill and Alex Livesey via Getty)

The emails released revealed that the four received medical exemptions to use banned drugs. The hackers wrote on their site that the U.S. has “disgraced its name by tainted victories,” attempting to delegitimize the athletes’ exemptions. It was possibly done as an act of revenge for the International Olympics Committee’s banning of 118 Russian competitors from the 2016 Olympics due to their involvement in a “state-sponsored doping program.” The Russian government denied any involvement, according to several news reports.

The World Anti-Doping Agency responded with a statement condemning the hackers. “WADA deeply regrets this situation and is very conscious of the threat that it represents to athletes whose confidential information has been divulged through this criminal act,” wrote Director General Olivier Niggli. “We are reaching out to stakeholders, such as the [International Olympic Committee], [International Sports Federations] and [National Anti-Doping Organizations], regarding the specific athletes impacted.”

Fancy Bear claims it will release more information on other national teams at a later date.

USA Gymnastics defended world-renowned Olympian Biles in a tweet:

Biles refuted the hackers’ allegations with her own social media message: 

The FBI also suspects hackers from Russia of releasing additional DNC emails yesterday. There are leaked emails from Former Secretary of State Colin Powell and others, on topics ranging from the Birther Movement to Hillary Clinton’s personal opinion on President Obama.