New Delhi:US sprinter and five-time Olympic medallist Marion Jones has failed a drug test at the US National Championships in Indianapolis in June. Results of the test were not made public because Jones' urine sample testing has not been completed yet. Only after the second half of her B sample results come out, will Jones be charged with a doping violation. The three-time gold medal winner would then face a two-year ban from track and field. She tested positive for erythropoitin, an endurance-boosting drug. Jones has been accused of doping earlier in 2003 also when the Bay Area laboratory co-operative drug scandal broke out, but she decalred herself innocent. If she tests positive, Marion Jones will become the third star American athlete to face similar charges after Floyd Landis and Justin Gatlin, within a very short span of time.