One of R. Kelly's alleged victims secretly testified against the singer in front of a federal grand jury that could indict him for tax evasion and sex trafficking.
Sources close to the case tell TMZ ... Faith Rodgers recently testified for a grand jury convened by U.S. Attorneys in the Southern District of New York, and we're told more witnesses are expected to provide testimony against Kelly soon.
No way to know what Faith told the panel -- federal grand jury proceedings are notoriously top secret -- but she's previously alleged Kelly gave her an STD and sued him last year for false imprisonment and sexual battery.
Faith was also featured in the Lifetime docuseries "Surviving R. Kelly" ... and afterward she claimed Kelly posted private photos of her and sent a notarized letter threatening to reveal details of her sex life in retaliation for her talking publicly.
We're told next week witnesses will testifying for a federal grand jury in Illinois, where Kelly is being investigated for tax evasion, obstruction of justice and sex trafficking.
We reached out to the U.S. Attorney's Office, but it declined to comment. Faith's attorney, Gloria Allred, would not confirm or deny her client testified.
Kelly's crisis manager, Darrell Johnson, says ... "Mr. Kelly feels like the devil is working overtime in effort to try to destroy his musical legacy for selfish, personal enrichment. We feel everything will line up right on track when it is all said and done."
Johnson added, "Mr. Kelly is not where he wants to be in life at this present moment. However, every indication shows that he is headed in the direction of a positive outcome. He feels that when you are very focused people try to take you down. He’s very confident that in the end he will be proven innocent.’’