London - US sprinter Tyson Gay, who pulled out of this months world athletics championships after a positive doping test, had taken a banned steroid, the BBC reported Friday.
The BBC said it had obtained extracts of a letter sent to Gay by the United States Anti Doping Agency (USADA) which said analysis of a sample showed values "consistent with the administration of a steroid of exogenous (external) nature."
The letter said a positive test for an "anabolic agent" of this kind would - if proven - be a violation of the World Anti-Doping Agency (WADA) code, the BBC reported.
USADA refused to comment on whether 30-year-old Gay, who has been provisionally suspended, had tested positive for a steroid, the report said.
However the agency confirmed on July 27 that the 2007 world 100m champion failed at least two tests.
It is understood that in addition to the positive sample he gave at the US trials in June, he failed an out-of-competition test in May, the report added.