May 06, 2006 4:30 PM EST

Two San Francisco Chronicle reporters who wrote a book about Barry Bonds' alleged steroid use were subpoenaed Friday to testify before a federal grand jury regarding court documents they used in their articles, the newspaper reported.

The subpoenas of the authors of Game of Shadows, Mark Fainaru-Wada and Lance Williams, called for them to turn over their copies of grand jury transcripts from the 2003 investigation of a steroid distribution ring based at the Bay Area Laboratory Cooperative, or BALCO, according to the Chronicle. They also were asked to provide the identity of the person or persons who leaked the secret documents to them.

Fainaru-Wada and Williams used the transcripts in their detailed reporting of the BALCO case that linked well-known athletes to the use of performance-enhancing drugs.

Chronicle executive editor Phil Bronstein insisted the reporters are protected under the First Amendment.

"The San Francisco Chronicle unconditionally stands by its reporters in fighting this effort by the government to force them to reveal their confidential sources," Bronstein said. "Reporters are not subject to the rules governing grand jury secrecy, which apply only to some of the people in the room during those proceedings."

Via FoxSports