IL HB4172

Amends the Code of Criminal Procedure of 1963 by adding Section 115-7.5 to allow evidence of prior offenses in criminal prosecutions for arson, aggravated arson, residential arson, place of worship arson, or possession of cannabis, controlled substances, or methamphetamine with intent to deliver

Permits evidence of defendant's prior commission of similar offenses to be admissible and considered for any relevant bearing on the case

Requires courts to weigh probative value against undue prejudice by considering: proximity in time to the charged offense, degree of factual similarity, and other relevant facts and circumstances

Mandates prosecution disclose evidence of prior acts, including witness statements or testimony summaries, at a reasonable time before trial or during trial if good cause shown for delay

Allows proof of prior acts through specific instances of conduct, reputation testimony, or expert opinion, with prosecution limited to offering reputation testimony only after the defendant has done so