It was five days ago that the International Swimming Federation, Fina, announced that 25-year-old Yevgeny Rylov will be suspended for nine months.
The reason was that he participated in a demonstration with President Vladimir Putin in March.
Despite the suspension, he participated in the Russian championships this weekend and because of that, Fina has initiated an investigation.
"Fina is aware that Rylov participated in the Russian championships this weekend and has initiated an internal investigation to see if Fina's sanctions or rules have been broken.
The results of the investigation will be announced shortly, "Fina writes in a statement to CNN.
Last Thursday, Fina announced that no Russian or Belarusian athletes will be allowed to participate in their competitions this year.