The 15-year-old star of Russia’s figure skating team who powered it to a win in the team figure skating competition tested positive for a banned substance at a national competition leading up to the Games, potentially throwing the team’s gold medal into doubt.

The skater, Kamila Valieva, was found to have used trimetazidine, a heart medication not normally allowed in competition, according to a statement Friday from the International Testing Agency.

It was unclear if Russia would be awarded the gold medal.

The decision, the testing agency said, can be taken by the International Skating Union, the sport’s governing body, “only after a final decision on the full merits of the case has been taken.” The International Olympic Committee did not immediately comment.

The award ceremony for the event, which Russia won Monday, beating the United States and Japan, had been delayed since Tuesday as International Olympic Committee officials said they were investigating a “legal issue.”

The award ceremony was supposed to take place Tuesday night in Beijing, with the American team to receive silver and Japan bronze. But just as the teams prepared to head to a plaza for the event, they were told to turn back.

Since then, Olympics officials had declined to elaborate on what is causing the delay.

Russia won the team event behind a breakout performance by Valieva.

The team event is a mixed-gender competition that made its debut at the 2014 Games in Sochi, Russia. A Russian team won that year and then claimed the silver medal behind Canada four years later in Pyeongchang, South Korea. The United States won the bronze medal in both previous editions.

This year, the American team, led by the three-time world champion Nathan Chen, finished second behind the Russian team in the best finish in the event for the U.S.

The team event is contested over several days. In it, each country is represented by men’s and women’s singles skaters, a pairs team and a set of ice dancers. The athletes compete in several rounds of performances, and the scores are combined to crown a winner.

The event can showcase the breadth of a team’s skating talent, but team events also come with risks. Germany and Ukraine failed to score points in portions of this year’s competition after losing athletes to positive coronavirus tests, ending their slim medal hopes.

But the disqualification of any athlete from a medal-winning team — a regular occurrence in other Olympic sports — mean the loss of that athlete’s points. That could alter the final standings.