As Kamila Valieva’s Olympics fate hangs in the balance with a Sunday hearing on the Russian figure skating star’s doping case, her coach insists the 15-year-old has done nothing wrong.

“We are absolutely sure that Kamila is innocent and clean,” Eteri Tutberidze told Russian state television on Saturday from Beijing.

Valieva helped the Russian Olympic Committee win a gold medal in the team event last week and is the heavy favorite for the women’s competition that is set to begin on Tuesday. But it remains to be seen whether she will be allowed to, after the International Testing Agency confirmed on Friday that she had tested positive for the banned substance trimetazidine, a heart medication.

The sample that tested positive was taken at the Russian national championships in December, but it was more than six weeks before it was submitted for testing and flagged as positive this past week. That put Valieva in the crosshairs in the midst of her first Olympics. Russia’s anti-doping agency provisionally banned Valieva on Tuesday — a day after she and the ROC won the team figure skating event — but lifted the ban a day later following an appeal.

The Court of Arbitration for Sport will hold a hearing Sunday, with a decision on Valieva’s fate expected to come by Monday afternoon in Beijing. That would determine whether the ROC will be awarded the gold medals for the team event that it won last week.

“It’s unclear why an athlete with a suspected doping on Dec. 25 was cleared to compete at the Olympics,” Tutberidze told Russian state television. “Either it is an ill-fated confluence of circumstances, or it’s a very well-planned plan. I hope our officials will not abandon us and defend our rights and prove our innocence.”

The ROC claimed in a statement that Valieva has “repeatedly passed doping tests” before and after the Dec. 25 test that turned out to be positive.

Valieva, who became the first in women’s competition to land a quad in Olympic history during the team event, has continued to practice for the individual competition. She has done so with all eyes on her, though, and on Saturday was in tears after a shaky practice, the Associated Press reported.

Tutberidze, who is coaching all three Russian women who are scheduled to compete in the women’s event, has also come under security. She is reportedly known for her demanding training methods and for coaching skaters who have dominant but short-lived careers.

Because Valieva is under 16 years old, her positive test for a banned substance has triggered an investigation into her “entourage,” which would include Tutberidze.

“On one hand, they are professional athletes, and they are competing at high level competitions as other adults [do] and should be ready to bear all their responsibility,” Margarita Pakhnotskaya, the former deputy CEO of the Russian anti-doping agency, told the Associated Press. “But on the other hand, we know that psychologically and mentally, they are not adults. And partly this responsibility should be shared with the senior people who are in their nearest circle.”

Valieva’s positive test has stoked high tensions at the Olympics and rekindled questions about Russia’s doping issues. The country’s athletes are competing under the ROC designation — without the Russian flag or anthem being involved in the Games — because of the state-sponsored doping scheme Russia allegedly ran during the 2014 Games in Sochi.

Senior IOC member Dick Pound said that, given the latest developments, Russia might need “a timeout” from the Olympics.

“The Russians don’t help themselves because they have been absolutely unrepentant,” Pound told Reuters. “They won’t admit anything, they appeal every single decision. … I think the approach probably has been too lenient to allow them to compete as the Russian Olympic Committee.”