R. Kelly, one of the top-selling recording artists of all time, has been dogged for years by allegations of sexual misconduct involving women and underage girls — accusations he and his attorneys have long denied.

But an Illinois prosecutor's plea for potential victims and witnesses to come forward and new protests have sparked hope among some advocates that the R&B star might face criminal charges.

"Please come forward. There's nothing that can be done to investigate these allegations without cooperation between victims and witnesses," Cook County State's Attorney Kim Foxx said Tuesday at a n...