The Olympic sprinter, Sherone Simpson, has told a Jamaican disciplinary panel that she never intentionally took a banned substance.
Simpson and the former 100-metre world record holder, Asafa Powell, both tested positive for the stimulant oxilofrone at the national championships in June.
The Olympic 4x100-relay gold and silver medallist insisted she is not a cheat, and blamed her positive doping test on a newly hired trainer who provided her with supplements.
Simpson said she had just recently begun working with Chris Xuereb, and that one of six supplements provided by him is responsible for the positive test.
Xuereb says he didn't give Simpson and Powell any performance-enhancing drugs and only purchased major brand vitamins
The hearing is expected to last at least two days.
