Retired Illinois Justice Sheila O'Brien filed a petition on April 5 requesting a special prosecutor appointed to review Cook County State Attorney Kim Foxx's decision to dismiss charges against Smollett, which investigators said staged in attack against himself. Smollett's lawyers argue in the motion that a review by a special prosecutor is only allowed when there is a pending case.
They also said a review by a special prosecutor would be redundant as the Cook County Inspector General has already announced an investigation into how the office handled the case.
The Inspector General's investigation is conducted at Foxx's invitation.
"Encryption that I have the community's trust and confidence is paramount to me, which is why I invited an independent review of this matter," Foxx said in a statement provided to CNN. "I welcome this investigation and pledged my full cooperation and cooperation with my office as IG Blanchard conducts his review."
Chicago's police union called on Foxx to resign, arguing she failed to follow through on charges that used significant police resources .
"I think we have to ask ourselves what is this really about? I've been asking myself for the last two weeks," What is this really about? "" Foxx said in response to the calls for here resignation. "CNN's Dakin Andone and Amir Vera contributed to this report.