The athletics coach at the centre of the BALCO scandal is expected in a United States district court in San Francisco today.
Trevor Graham is facing three charges of lying to federal investigators about the provision of performance-enhancing drugs to some of the biggest names in athletics.
Former sprinter Graham, who represented Jamaica at the Seoul Olympics in 1988, faces up to 15 years in jail for his role in the supply of drugs to the likes of Marion Jones, Tim Montgomery and 2004 Olympic 100-metres champion Justin Gatlin.
Graham, 44, has pleaded not guilty.
Many of Graham's former charges are expected to testify that Graham helped them get human growth hormone, the blood-booster EPO and other performance-enhancing drugs.
Graham sparked the investigation into the Bay Area Laboratory Co-operative (BALCO) when he anonymously sent a syringe of the anabolic steroid THG, which had been chemically designed for avoid detection, to the drug-testing laboratory at the University of California.
The witness list includes Jerome Young and Antonio Pettigrew, team-mates on America's 4x400 metres relay team who won at the Sydney Games in 2000, and Dennis Mitchell, who finished third in the 1992 Olympic 100m final.
Graham's former assistant Randall Evans is also expected to testify, as is Angel Heredia, a former Mexican national discus champion, who claims that he was Graham's steroid supplier.
Neither Jones not Montgomery will give evidence. Both are in prison - Jones serving six months for lying to federal investigators, for almost four years for cheque fraud.
Gatlin is also required to testify because he has not admitted to knowingly taking banned drugs.
Graham must answer felony charges following statements he made concerning his contact with Heredia.
He is accused of lying during a June 2004 interview with federal agents after he was given immunity from prosecution, unless he lied.
Graham denied he had met Heredia in person, denied he had talked to him on the telephone since 1997, and denied he had obtained performance-enhancing substances from Heredia or referred athletes to him for drugs.
The athletics world is braced for revelations about as-yet unnamed stars during the court case with Victor Conte, the founder and owner of BALCO, claiming there are world champions who have used THG but have escaped exposure so far.