BEIJING (AP) — Olympic favorite Kamila Valieva tested positive for a banned heart medication before her arrival at the Beijing Olympics, the Russian newspaper RBC reported, putting in jeopardy the team gold medal that she helped win earlier this week.

The sample was reportedly obtained in December, when the 15-year-old Valieva was still in Russia, but did not come to light until after she had helped her team win the gold medal with dynamic performances in her short program and free skate.

If the Russian team is disqualified, the U.S. team would be elevated to gold, Japan to silver and fourth-place finisher Canada — the defending champion in the team event — would receive the bronze medal.

Valieva made history during the event. She became the first woman to land a quadruple jump.

She is the favorite for the gold medal in the individual event. It's unclear whether she will still be allowed to compete.