Olympic cycling: Russian cyclist Baranova expelled for doping

London - Russian track cyclist Victoria Baranova has been caught doping and sent home from the London Olympics, according to reports.

Baranova, 22, was due to participate in Friday's keirin finals, but was expelled from the team by the Russian Cycling Federation after testing positive for a prohibited substance.

The nature of the substance and the timing of the failed test were unclear but according to sources Baranova has admitted her guilt.

Baranova, ranked No. 2, had trained under the supervision of her father, Alexei, in the run-up to the Games, separately from the Russian team.

She won the keirin in the European junior track championships in Portugal last month.

Baranova is the third drugs cheat to be caught during the Games after Albanian weightlifter Hysen Pulaku tested positive for steroids and Uzbek gymnast Luiza Galiulina was found to have  taken a drugs masking agent.

Additionally, the Olympic committee of St. Kitts and Nevis Sunday sent home sprinter Tameka Williams for taking a substance that they feared "would fall outside the accepted medical code."

More than 100 athletes were prohibited from competing in London for doping offences that were uncovered in the six months leading up to the Games, the IOC announced Friday.