The World Anti-Doping Agency (WADA) will not rule out the possibility of levying additional sanctions against Olympic and world champion swimmer Sun Yang, following his controversial doping violation.

Sun received a ban of three months from the China Anti-Doping Agency (CHINADA), following a failed drug test during the national swimming championships on May 17. His short suspension and CHINADA’s belated announcement of the case have sparked widespread debate about the leniency of his ban.

WADA spokesman Ben Nichols said that the agency has not yet received the full facts of Sun’s case.

“WADA may decide whether to appeal to the Court of Arbitration for Sport demanding additional punishment after the investigation,” Nichols added.

An additional punishment may hinder Sun’s attempts to qualify for the 2016 Summer Olympics, to be held in Rio de Janeiro, Brazil