- The international swimming federation's executive director, Brent Nowicki, has been ordered to testify as a witness in a U.S. criminal investigation.

- The investigation is regarding 23 Chinese swimmers who tested positive for a banned substance, trimetazidine, in 2021 but were allowed to continue competing.

- The Chinese swimmers won three gold medals at the 2021 Tokyo Olympics, and 11 of them are set to compete in the upcoming Paris Olympics.

- The positive tests were kept secret in 2021, and WADA accepted the Chinese authorities' explanation of food contamination at a hotel.

- The U.S. federal law, Rodchenkov Anti-Doping Act, passed in 2020, allows probes into suspected doping conspiracies even if they occurred outside the U.S.

- The investigation could make sport officials traveling to the U.S. "fearful that they may have to answer questions about their activities from the FBI."