HAVANA, Cuba (AFP) – Disgraced Cuban discus thrower Yarelys Barrios has vowed to fight to prove her innocence after being caught doping in re-tested samples from the Beijing 2008 Olympics.

Barrios originally took silver at the Beijing Games before also winning bronze in London four years later, although only after Russian Darya Pishchalnikova was disqualified after testing positive for an anabolic steroid.

The 33-year-old Barrios tested positive for the diuretic and potential masking agent acetazolamide in results published by the International Olympic Committee on Thursday.

She has been ordered to return her medal but some reports claim she has already sold it on eBay for around $11,000 (10,500 euros).

“The only doping I know is the sun I caught on the track and the weights I’ve lifted in my life,” said a defiant Barrios.

“However, I remain hopeful it’s a mistake, I’ve always been clean.”

Barrios insisted she’s never taken doping products and called for an investigation into possible “manipulation” of her sample.