A federal judge denied a motion by the U.S. Anti-Doping Agency Friday to obtain the sealed grand jury testimony of the four athletes it is attempting to ban for life from track and field for alleged doping offenses.

The agency has sought for weeks to obtain the testimony for its pending arbitrations, according to lawyers with knowledge of the letters.

Several sources said at least some of the athletes charged by USADA admitted taking banned drugs to the grand jury convened in the federal steroid investigation surrounding the Bay Area Laboratory Co-Operative. Had U.S. District Judge Susan Illston granted the motion during Friday's hearing in San Francisco, it would have made victory in at least some of the arbitrations a virtual lock for USADA.

Instead, the agency will have to rely on the circumstantial evidence it has procured from a federal raid of BALCO to try to ban the athletes from the Athens Games. None of the athletes has failed a drug test in connection with this case.

Before filing its motion, USADA made repeated requests to the four athletes -- Tim Montgomery, Chryste Gaines, Michelle Collins and Alvin Harrison -- to take the legal steps necessary to obtain their own testimony. Lawyers for all of the athletes rejected those requests.

It is extremely unusual for the courts to release grand jury testimony to any party for any reason. USADA argued that the testimony would help the United States field a clean team at the 2004 Olympics.

"Did these people take these substances or didn't they?" Bob Vizas, a USADA attorney, told Illston, according to the Associated Press. "We want to see the right people compete in the Olympics."

Illston, however, supported the government's view that USADA did not have a compelling enough need to violate the secrecy that testifying in front of a grand jury is supposed to guarantee.