American swimming champion Lilly King has called Shayna Jack a 'drug cheat' after the Australian confirmed she had tested positive for a banned substance.
At a world swimming titles where Mack Horton has taken an anti-doping stance against Sun Yang, American champion Lilly King says she considers Australia's Shayna Jack a "drug cheater" like the Chinese star.
After initially claiming Jack had left the world titles team for "personal reasons", Swimming Australia said on Saturday the 20-year-old had actually failed a routine out of competition drug test on 26 June.
Swimming Australia could not provide any more details about the results.
News of Jack's failed test broke at a world titles campaign in South Korea where Australia's Horton has caused international headlines for his stand against Sun.
Horton refused to join Sun - who served a drug ban in 2014 - on the podium after the Chinese star relegated him to 400m freestyle silver, sparking an international furore.
US breaststroke champion King has also been an outspoken critic of Sun at the titles.
Swimmers were angry Sun had been allowed to contest the titles ahead of a Court of Arbitration for Sport hearing in September.
But when a Chinese reporter asked King why she called Sun a cheat and not Jack, King said: "She is a drug cheater.
"She has tested positive on a drug test. I don't know the details on the case so we will see."
But King did not think Jack's positive test had tarnished Australian Horton's anti-doping crusade at the titles in Gwangju.
"I don't think necessarily, I think all swimmers are standing up for clean athletes," she said.
"It shouldn't matter what country they're from even if they're from your own country - doping is doping so I don't think it should affect the protest too much."
Australian veteran Cate Campbell said no member of the Dolphins team knew of Jack's positive test.
"I had absolutely no knowledge of this before tonight. All I knew before is that it was a personal matter and we were respecting her privacy," she said.
"I think that we have to respect the process. We stand for clean sport and I think the fact that Shayna isn't here at the moment strengthens that stance."
Jack confirmed the positive test on Instagram but said she did not "knowingly" take a banned substance.
"It is with great sadness and heartache that I had to leave due to allegations of having a prohibited substance in my system," she posted.
"I did NOT take this substance knowingly. Swimming has been my passion since I was 10 years old and I would never intentionally take a banned substance that would disrespect my sport and jeopardise my career.
"Now there is an ongoing investigation and my team and I are doing everything we can to find out when and how this substance has come into contact with my body."
Eyebrows were raised when Jack withdrew from the Dolphins' squad just days before the world titles started.
Swimming Australia did not elaborate on the reasons at the time.
They were more forthcoming on Saturday.
"Once Swimming Australia was made aware of the adverse test result, it immediately took action - in accordance with the national policy - to provisionally suspend Shayna from the Australian swim team while a process was underway and accompanied her back to Australia from a training camp being held in Japan," a statement said.
"The Swimming Australia policy also means that any Australian athlete under provisional suspension, while ASADA investigations are underway, cannot take part in any competition, meaning Shayna was unable to travel to Gwangju to compete at the 2019 World Championships."
"Under the process, all details are required to remain confidential until ASADA has completed its investigations, the athlete is afforded due process and an outcome determined."