Several members of the Chinese national swimming team remain embroiled in a doping scandal. 

The swimmers in question have been under fire since testing positive for the banned heart medication trimetazidine in 2021.

The World Anti-Doping Agency (WADA) ultimately cleared the athletes for competition at the Tokyo Olympics. 

Last month, the Chinese Swimming Association selected some of those athletes for its 2024 Olympic team. The swimmers are preparing to travel to compete in Paris later this month.

But on Thursday, World Aquatics revealed that its top administrators had been ordered to testify as witnesses in a U.S. criminal investigation into the case of the 23 Chinese swimmers.

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A view of the Paris La Defense Arena

The Paris La Defense Arena in Nanterre, France, will host swimming and some water polo events during the upcoming Paris Olympic Games.  (AP Photo/Thomas Padilla)

The Chinese swimmers won three gold medals at the 2021 Tokyo Olympics, a few weeks after WADA said the swimmers' positive tests were at least partially due to inadvertently being exposed to the substance through "contamination." 

The Chinese Doping Agency initially made a similar argument, to which WADA said it was "not in a position to disprove."  

SEVERAL CHINESE SWIMMERS EMBROILED IN DOPING SCANDAL SELECTED FOR PARIS OLYMPICS: REPORT

Those decisions, which World Aquatics also separately reached, were later made public in April via reporting by The New York Times and German broadcaster ARD.

A House committee on China on May 21 asked the Justice Department and the FBI to investigate the case under a federal law that allows probes into suspected doping conspiracies even if they occurred outside the U.S.

A view of an olympic swimming pool

A view of the Olympic swimming pool at the Paris La Defense Arena in Nanterre, France, outside Paris. (AP Photo/Thomas Padilla)

"World Aquatics can confirm that its executive director, Brent Nowicki, was served with a witness subpoena by the United States government," the federation 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."

Legendary American swimmer Michael Phelps testified before a congressional committee last month. The ongoing case was mentioned during the hearing, and Phelps said athletes have lost faith in WADA as the global watchdog that is responsible for keeping cheaters out of sports.

WADA officials rejected an invitation to come to the hearing, saying it would be "inappropriate to be pulled into a political debate before a U.S. congressional committee regarding a case from a different country, especially while an independent review into WADA’s handling of the case is ongoing."

Michael Phelps, Travis Tygart and Allison Schmitt testify

From left: Former Olympic athlete Michael Phelps, U.S. Anti-Doping Agency CEO Travis Tygart and former Olympic athlete Allison Schmitt are sworn in during a House Committee on Energy and Commerce Subcommittee on Oversight and Investigations hearing examining Anti-Doping Measures in Advance of the 2024 Olympics on Capitol Hill in Washington, D.C., on June 25. (AP Photo)

Travis Tygart, CEO of the U.S. Anti-Doping Agency, suggested to the AP that an ongoing federal investigation could make sports officials traveling to the U.S. "fearful that they may have to answer questions about their activities from the FBI."

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The U.S. is set to host the 2028 Summer Games in Los Angeles. It will mark the first time the Summer Games will be held in an American city since Atlanta hosted the 1996 Olympics.

Salt Lake City is slated to host the 2034 Winter Games.

The Associated Press contributed to this report.

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