725 ILCS 5/104-11 : Rights and Remedies — Criminal Procedure — Code of Criminal Procedure of 1963 — General Provisions — Fitness For Trial, To Plead or To Be Sentenced —11 - Raising Issue; Burden; Fitness Motions

(a) The issue of the defendant's fitness for trial, to plead, or to be sentenced may be raised by the defense, the State or the Court at any appropriate time before a plea is entered or before, during, or after trial. When a bonafide doubt of the defendant's fitness is raised, the court shall order a determination of the issue before proceeding further.
(b) Upon request of the defendant that a qualified expert be appointed to examine him or her to determine prior to trial if a bonafide doubt as to his or her fitness to stand trial may be raised, the court, in its discretion, may order an appropriate examination. However, no order entered pursuant to this subsection shall prevent further proceedings in the case. An expert so appointed shall examine the defendant and make a report as provided in Section 104-15. Upon the filing with the court of a verified statement of services rendered, the court shall enter an order on the county board to pay such expert a reasonable fee stated in the order.
(c) When a bonafide doubt of the defendant's fitness has been raised, the burden of proving that the defendant is fit by a preponderance of the evidence and the burden of going forward with the evidence are on the State. However, the court may call its own witnesses and conduct its own inquiry.
(d) Following a finding of unfitness, the court may hear and rule on any pretrial motion or motions if the defendant's presence is not essential to a fair determination of the issues. A motion may be reheard upon a showing that evidence is available which was not available, due to the defendant's unfitness, when the motion was first decided.

725 ILCS 5/104-11

P.A. 81-1217.