MAY 2014

Banned for three months by the Chinese Swimming Association after testing positive for the stimulant trimetazidine, which had been added to the World Anti-Doping Agency's (Wada) banned list four months earlier.

Sun argued it had been prescribed by a doctor to treat heart palpitations, a problem he has suffered since 2008, and was unaware it was now prohibited.

Chinada, the Chinese anti-doping agency, concluded Sun "proved with sufficient evidence that he did not intend to cheat", and Wada also elected not to proceed further after reviewing his case file.

AUGUST 2016

Mack Horton and Sun clashed at the Rio Olympics, with the latter said to have splashed water at his Australian rival during a practice session, just days before they faced off in the 400m freestyle.

In response to that incident, Horton, who went on to clinch the gold 0.13sec ahead of runner-up Sun, said: "I ignored him, I don't have time or respect for drug cheats."

JANUARY 2019

The Times of London reported that last September, Sun and a security guard smashed a vial of blood with a hammer to prevent anti-doping test collectors from leaving his home with a sample.

Two out of three of the testers did not have the proper accreditation and according to ABC News, Sun had "noticed anomalies" with the paperwork.

Also, it reported that "one of the testing entourage was at the time taking photos and taking video of the swimmer without authority or permission to do so".

JULY 14, 2019

Australia's Sunday Telegraph published the contents of the doping panel report, with Fina letting Sun off on a legal technicality and clearing him to compete at the on-going world championships in Gwangju, South Korea.

Wada has, however, appealed to the Court of Arbitration for Sport (CAS) and the hearing is set to be heard in September.

This has led to multiple protests at the world meet, notably by Horton and Briton Duncan Scott, with the duo refusing to join Sun on the podium after competing against him.

AGENCE FRANCE-PRESSE