The Illinois Supreme Court reversed an appellate court decision in *People v. Heintz*, addressing critical questions about evidence admissibility in domestic violence prosecutions. The case involves William P. Heintz, who was charged with attempted first degree murder, aggravated domestic battery, unlawful restraint, and domestic battery in connection with his conduct toward Brianne Szalaj on Aug. 6, 2020.
The high court's opinion, filed Jan. 28, 2026, and delivered by Justice Theis, focused on two key evidentiary issues that have implications for how domestic violence cases are prosecuted in Illinois. Justice Theis was joined by Justices Overstreet, Holder White, and Rochford in the majority opinion, while Justice O'Brien filed a special concurrence joined by Chief Justice Neville and Justice Cunningham.
The first issue before the court involved whether evidence of Szalaj's alleged violent conduct that occurred after the charged offenses against Heintz could be admitted under Illinois Rule of Evidence 405(b)(2). This rule governs the admissibility of character evidence through specific instances of conduct, and its application in this context raises questions about how courts should handle evidence of an alleged victim's behavior that postdates the crimes for which a defendant is being prosecuted.
The second major question addressed whether the Kankakee County circuit court abused its discretion when it barred evidence that Heintz had been acquitted of one of four prior alleged acts of domestic violence against Szalaj. The State had introduced evidence of these prior acts at trial, but the trial court prevented the defense from presenting evidence of the acquittal on one of those charges.
Prior to trial, both the prosecution and defense had sought to introduce evidence of other acts of violent conduct that occurred during Heintz's multiyear relationship with Szalaj. This type of evidence often becomes contentious in domestic violence cases, as prosecutors seek to establish patterns of abuse while defense attorneys argue such evidence is prejudicial and irrelevant to the specific charges at hand.
The case reached the Supreme Court after the Illinois Third District Appellate Court vacated Heintz's convictions and remanded for a new trial. The appellate court's decision in *People v. Heintz* (2024 IL App (3d) 230161-U) had found errors in the trial court's handling of the evidence questions, leading to the reversal of Heintz's convictions.
The Supreme Court's decision to reverse the appellate court's judgment and remand the case back to the appellate court indicates that the high court disagreed with at least some aspects of the lower court's analysis. However, the court also directed the appellate court to consider Heintz's remaining claims, suggesting that while the evidence issues may have been resolved in the State's favor, other aspects of the case still require appellate review.
The ruling comes at a time when courts across the country are grappling with how to balance the rights of defendants with the need to protect domestic violence victims and ensure fair prosecutions. Evidence rules in domestic violence cases can be particularly complex because they often involve ongoing relationships where multiple incidents may have occurred over time.
Illinois Rule of Evidence 405(b)(2) allows for the admission of specific instances of conduct to prove character when character is an essential element of a charge or defense. The rule's application to evidence of an alleged victim's post-offense conduct represents a nuanced area of evidence law that could affect how similar cases are handled in the future.
The question of whether courts can exclude evidence of a defendant's acquittal on related charges also touches on fundamental fairness concerns in the criminal justice system. Defense attorneys often argue that such acquittals are highly relevant to a defendant's case, while prosecutors may contend that acquittals don't necessarily mean conduct didn't occur, only that it wasn't proven beyond a reasonable doubt.
The case reflects the ongoing evolution of domestic violence law in Illinois and the broader challenge of ensuring that evidence rules serve both the interests of justice and the protection of all parties involved in these often complex and emotionally charged cases.
While the Supreme Court's full reasoning will be contained in the complete opinion, the decision to reverse the appellate court suggests that Illinois will maintain certain standards for evidence admissibility that may favor prosecution arguments in domestic violence cases. The remand to the appellate court ensures that other aspects of Heintz's appeal will still receive appropriate judicial review.
The case serves as an important precedent for Illinois courts handling similar evidentiary questions in domestic violence prosecutions and provides guidance on the proper application of state evidence rules in these sensitive cases.