The international swimming federation, World Aquatics, has confirmed that its executive director, Brent Nowicki, has been subpoenaed to testify in a U.S. criminal investigation into the case of 23 Chinese swimmers who tested positive for a banned substance in 2021 but were allowed to continue competing.

This development comes just three weeks before the Paris Olympics, where 11 of these swimmers are scheduled to compete.

On May 21, the House Committee on China requested the Justice Department and the FBI to investigate this case under a federal law that allows investigations into suspected doping conspiracies even if they occurred outside the U.S.

World Aquatics told The Associated Press on Thursday that Nowicki received a subpoena to testify in the investigation.

“World Aquatics can confirm that its executive director, Brent Nowicki, was served with a witness subpoena by the United States government,” World Aquatics said in a statement to The Associated Press. “He is working to schedule a meeting with the government, which, in all likelihood will obviate the need for testimony before a Grand Jury.”

World Aquatics declined to provide details about where and when Nowicki received his subpoena and did not disclose which office is handling the investigation. The FBI did not immediately respond to requests for comment.

The swimmers in question were permitted to compete at the Tokyo Olympics despite testing positive for a banned heart medication just months prior to the games. Chinese officials attributed this to food contamination, and the World Anti-Doping Agency accepted this explanation and has defended its handling of the situation.

The positive tests were not publicly known until the New York Times and German broadcaster ARD initially reported on the case earlier this year.