Section 735 ILCS 5/10-124 - Causes for discharge when in custody on process of courtIf it appears that the prisoner is in custody by virtue of process from any court legally constituted, he or she may be discharged only for one or more of the following causes:
1.Where the court has exceeded the limit of its jurisdiction, either as to the matter, place, sum or person.2.Where, though the original imprisonment was lawful, nevertheless, by some act, omission or event which has subsequently taken place, the party has become entitled to be discharged.3.Where the process is defective in some substantial form required by law.4.Where the process, though in proper form, has been issued in a case or under circumstances where the law does not allow process to issue or orders to be entered for imprisonment or arrest.5.Where, although in proper form, the process has been issued in a case or under circumstances unauthorized to issue or execute the same, or where the person having the custody of the prisoner under such process is not the person empowered by law to detain him or her.6.Where the process appears to have been obtained by false pretense or bribery.7.Where there is no general law, nor any judgment or order of a court to authorize the process if in a civil action, nor any conviction if in a criminal proceeding. No court, on the return of a habeas corpus, shall, in any other matter, inquire into the legality or justice of a judgment of a court legally constituted.