Russian skater Kamila Valieva's lawyers have said her failed doping test may have been caused by her grandfather's medication contaminating a glass she drank from.
Sports lawyer Denis Oswald said part of the 15-year-old athlete's defence is "contamination which happened with a product her grandfather was taking".
This argument was presented at a Court of Arbitration for Sport (CAS) hearing on Sunday night.
Her lawyers said the glass of water may have contained traces of her grandfather's heart medication and could be responsible for Kamila Valieva's positive doping test, which found the presence of traces of the banned substance trimetazidine.
Valieva's lawyer Anna Kozmenko told the CAS panel on Sunday: "There can be completely different ways how it got into her body," according Russian newspaper Pravda.
Kozmenko is reported to have said: "For example, her grandfather drank something from a glass, some saliva got in, this glass was somehow later used by an athlete. Or the drug was laid down on some surface, traces remained, the drug lay down on this surface, which the athlete then drank."
However, despite testing positive for a banned heart medication, the judges ruled that Valieva could compete in Monday's women's individual event at the Winter Olympics.
Although she will be permitted to skate, the investigation will continue for months, and depending on its findings, Valieva may be stripped of her medals at a later date.
The athlete was pinned as a favourite in her women's event and helped the Russian team win gold last week.
Valieva will be investigated by the Russian anti-doping agency after the Olympics.
Oswald said Valieva's representation "presented elements that brought some doubts about her guilt."
The CAS panel said their decision to let the teenager skate was made due to her status as a minor, the potential harm to her career and the delay in informing Russia about the positive test from a sample taken on Dec. 25.
However, the International Olympic Committee has said even if the skater places in the competition, no medals will be given to Valieva until after the full investigation is complete.
