The World Anti-Doping Agency on Saturday dismissed speculation it did not respond properly to positive doping tests of 23 Chinese swimmers ahead of the Tokyo 2021 Olympics where several of them competed after all were cleared.
WADA said it conducted a thorough review process and "reserves its right to take legal action as appropriate ... following the misleading information that has been published this week."
German broadcasters ARD, the New York Times and Australian paper Daily Telegraph reported earlier Saturday that the governing body World Aquatics, then FINA, and WADA were satisfied with the Chinese explanation that contaminated food had led to the positive tests.
ARD Sportschau said that its investigation together with the New York Times revealed that the swimmers tested positive for the banned heart medication trimetazidine (TMZ) at a domestic competition in Shijiazhuang in early 2021.
The reports based on receiving the Chinese report last September said that China's anti-doping agency CHINADA reported the cases to FINA and WADA.
No sanctions were imposed because the positive tests were deemed to come from contamination after China said its investigators found traces of TMZ in various areas of the kitchen were the meals for the athletes had been prepared.
The swimmers were cleared to continue competing in June 2021 and the case never became public. A 30-strong Chinese team, including 13 of the 23 with positive tests, went on to win six medals in Tokyo, including three gold medals.
WADA said it was unable to investigate in China due to coronavirus restrictions at the time but conducted an extensive review whether the Chinese decision was credible.
"The WADA Science Department reviewed this case thoroughly in June and July 2021," WADA science director Olivier Rabin said.
"Indeed, we even sought new pharmacokinetic and metabolism information on TMZ from the manufacturer and tested several hypotheses, including doping strategies with low TMZ doses, in assessing the plausibility of the contamination scenario that was presented to WADA.
"Ultimately, we concluded that there was no concrete basis to challenge the asserted contamination. Indeed, the contamination scenario was further supported by the combination of the consistently low concentrations of TMZ as well as no doping pattern with several athletes presenting multiple samples collected over the course of several days which fluctuated between negative and positive (and vice versa).
"In all transparency, we communicated the conclusions of our scientific review to internal and external investigators, including the International Testing Agency.”
World Aquatics told the Daily Telegraph that the case was "subject to independent expert scrutiny" and that it was confident the issue was "handled diligently and professionally, and in accordance with all applicable anti-doping regulations, including the World Anti-Doping Code.”
WADA saidit was also alerted to the cases in 2022 by the International Testing Agency and last year by the US Anti-Doping Agency (USADA).
It said it told the ITA that all procedures were correctly followed and USADA's claim that the cases had been hidden was wrong because China had reported them.
There have been other doping cases involving TMZ, most notably that of young Russian figure skater Kamila Valieva whose positive test in December 2021 was announced during the Beijing 2022 Winter Olympics. Valieva was later banned for four years.