Federal prosecutors in Chicago have asked for a protective order on all evidence turned over in the sexual abuse case against singer R. Kelly, telling a judge Thursday that putting sensitive material in the public domain would have a “chilling effect” on cooperating witnesses.

In asking for the blanket protective order on discovery, Assistant U.S. Attorney Angel Krull also said the government may seek to supersede the indictment against Kelly and two former associates, possibly adding "additional charges and additional defendants” as the case progresses.

Krull told U.S. District Judge Harry Leinenweber that evidence Kelly and his entourage obstructed justice in his 2008 trial on child pornography charges was particularly sensitive. Some victims have been repeatedly harassed by Kelly’s followers, while other witnesses “have been hesitant to come forward and cooperate with the government,” she said.

“They don’t want their names out there,” Krull said. “They don’t want to be hounded by the press (or) fans of Mr. Kelly. … One witness had to quit her job (because of the harassment).”