Olympic 100m hurdles champion Brianna McNeal has been provisionally suspended after being charged with a doping violation.
The Athletics Integrity Union announced on Thursday that the 29-year-old, who also won the world title in 2013, is accused of "tampering with any part of doping control."
McNeal served a one-year ban in 2017 after missing three drugs tests, admitting later that she took "full responsibility" for the "mistakes" that led to her failing to update her whereabouts.
Because of her previous suspension, McNeal faces an extended ban of up to eight years if the latest charge against her is upheld.
McNeal won Olympic gold at the 2016 Rio Olympics. Her quest for a second world title ended in Doha last year when she was disqualified for a false start in the heats.
She is the fourth fastest woman in history in her event. She clocked 12.26 seconds at the US national championships.
Australian Associated Press