SAN FRANCISCO -- Federal prosecutors are not done crafting their criminal case against suspended state Sen. Leland Yee and more than two dozen defendants, raising the possibility they may add racketeering charges against some of the players caught in their sprawling investigation.

The government plans to revise its indictment within the next 90 days, Assistant U.S. Attorney Susan Badger told a federal judge during a court hearing Friday, though she did not specify the potential new charges. U.S. District Judge Charles Breyer gave prosecutors until July 20 to bring their so-called superseding indictment, a common move by federal prosecutors to refine a criminal case after its initial charges.

State Sen. Leland Yee leaves Federal Court in San Francisco after posting $500,000 bail March 26, 2014, after his arrest on federal weapons charges. (Karl
State Sen. Leland Yee leaves Federal Court in San Francisco after posting $500,000 bail March 26, 2014, after his arrest on federal weapons charges. (Karl Mondon/Bay Area News Group)

Court papers indicate that the prosecutors may add defendants to the case and also are considering racketeering charges. There was no indication Yee, already charged with gun trafficking and political corruption, would be swept up in a racketeering case.

Legal experts have speculated the government may be considering a racketeering charge to tie together its case against a host of defendants charged with everything from money laundering and gun trafficking to drug dealing and trafficking in stolen cigarettes and booze. But experts have questioned whether that strategy would be effective against Yee, who has a direct connection to only two or three of the 28 other defendants in the case.

The 65-year-old San Francisco Democrat has pleaded not guilty to federal charges of gun trafficking, conspiracy and committing honest services fraud, accused of promising political favors in exchange for money from undercover FBI agents. Yee sat in the courtroom during Friday's routine hearing, and left the courthouse without comment.

Questions are being raised already about how unwieldy the government's overall case is, given the large number of defendants accused of a disparate set of crimes. Breyer remarked during Friday's hearing that there would not be a single trial for so many defendants.

James Brosnahan, the lawyer for indicted San Francisco political consultant Keith Jackson, said large numbers of groups within the indictment are "not together in any allegations," suggesting the judge could dismiss the charges altogether because of such tenuous ties between many of the defendants. Jackson is portrayed in the case as the original link between undercover agents and Yee.

Breyer set another hearing in the case for next week, when the lawyers will settle on methods for receiving the government's trove of evidence, including wiretapped conversations.

In the meantime, some of the defense lawyers have gone on the offensive, attacking the government's case as entrapment and overreaching. Tony Serra, the lawyer for Raymond "Shrimp Boy" Chow, a central figure in the case, this week lashed out at prosecutors and the FBI, saying they "fabricated" the case.

"There's definitely two sides to the story," Serra told reporters Thursday in his North Beach law office, surrounded by Chow backers wearing bright red "Free Shrimp Boy" T-shirts.

"Only when the case randomly pointed toward Yee, they had the celebrity defendant they wanted all the time. If Yee hadn't been involved, maybe my client would never have been charged."

Howard Mintz covers legal affairs. Contact him at 408-286-0236 or follow him at Twitter.com/hmintz