(CNN) -- U.S. Olympian LaShawn Merritt, a gold medalist in track and field, was suspended Monday after testing positive for banned steriods almost a year ago, according to the U.S. Anti-Doping Agency.
Merritt tested positive for DHEA last year, was placed on a provisional suspension and was "disqualified from all competitive results achieved at and subsequent to October 28, 2009, including forfeiture of any medals, points, and prizes", said the statement from the USADA.
The decision was made by an independent three-member American Arbitration Association panel that's been investigating the doping violation, the agency said. The 21-month period of ineligibility dates back to the day the first sample was collected, said Nick Esares, communications representative with the USADA.
The track star won gold medals in the men's 400 meters and 400-meter relay at the 2008 Beijing games in China.
In April, a statement released by Merritt said the use of the substance was the inadvertent result of taking an over-the-counter "male enhancement" pill "and occurred at a time that he was neither seriously training nor competing."
In a statement issued through his attorney in April, Merritt said he had accepted a provisional suspension. Merritt's attorney, Howard Jacobs, said the athlete was notified of the positive results in March and was "shocked and saddened" by the news.
Calls to Jacobs' office Friday, after the suspension was announced, were not immediately returned.