Jamaican sprinter Steve Mullings is determined to prove his "innocence to the world" following a life ban for a second doping offence.
The 28-year-old tested positive for the banned diuretic furosemide, which can act as a masking agent for other drugs.
He previously served a two-year ban after testing positive for excessive levels of testosterone in 2004.
"Myself and my attorneys are focusing our time and energy on proving my innocence to the world," Mullings said.
The sixth fastest man of all time over 100m is expected to appeal against the ruling to the Court of Arbitration for Sport (CAS), after Jamaica's anti-doping disciplinary panel imposed the life-long ban.
"I am extremely disappointed in the decision made by the panel on Monday afternoon," he told BBC Sport. "I am unable to comment any further on this matter."
His attorney, Alando Terrelonge, said the decision was unfair based on the evidence presented to the panel.
"There was no evidence before this panel to indicate that Mr Mullings either deliberately took a drug to enhance his performance or mask the presence of other drugs that he was taking to enhance his performance," he said.