A former New York Mets' clubhouse attendant, Radomski was sentenced to five years' probation after pleading guilty to distributing steroids and laundering money. He was escorted out of the restricted-access grand-jury area by an officer shortly before 12:30.
Assistant U.S. Attorney Daniel P. Butler left the grand-jury area shortly thereafter, about two hours after arriving at the court house. Butler would not comment on his way in or out.
Radomski led investigators to Clemens' former personal trainer, Brian McNamee, who told federal agents and baseball investigator George Mitchell that he injected Clemens more than a dozen times with steroids and HGH from 1998-01.
Radomski and McNamee figure to be among the primary witnesses against the seven-time Cy Young Award winner. McNamee last year provided government agents with syringes his lawyers said would link Clemens to drug use.
McNamee is to meet with prosecutors in Washington on Friday, a person familiar with the investigation said, speaking on condition of anonymity because the session was to be private. McNamee's meeting originally had been set for Tuesday but was postponed.
Congress asked the Justice Department to look into whether Clemens lied last February, when he testified under oath at a deposition and a public House hearing that he never took illegal performance enhancers.
The Justice Department brought the case to a grand jury after an 11-month FBI inquiry. A grand jury allows prosecutors to get sworn testimony from witnesses and collect documents.
AP Baseball Writer Ronald Blum in New York contributed to this report.
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