Illinois Investigates Suburban Police Department for Sharing License Plate Data in Abortion-Related Case

Illinois secretary of state Alexi Giannoulias

The Illinois Secretary of State has called for a formal investigation into the Mount Prospect Police Department following revelations that it shared automatic license plate reader (ALPR) data with a Texas sheriff searching for a woman who had obtained an abortion. The data-sharing move appears to violate a 2023 Illinois law that restricts how such surveillance information can be used.

Secretary of State Alexi Giannoulias formally requested the Illinois Attorney General's Office to review the incident, while also announcing the creation of an audit mechanism to ensure local law enforcement agencies comply with the law. The 2023 legislation, which Giannoulias championed, bans sharing license plate data to track women seeking reproductive healthcare or to investigate undocumented immigrants.

According to Giannoulias, the Mount Prospect Police Department, located roughly 24 miles northwest of Chicago, transmitted license plate data to law enforcement officials in Johnson County, Texas. The Texas sheriff was attempting to locate a woman whose family expressed concern after she reportedly underwent a self-managed abortion. The exchange of data allegedly violated the Illinois law, which was passed in response to growing concerns that states banning abortion would attempt to use surveillance tools to target patients crossing state lines to seek care in Illinois, where abortion remains legal and protected.

“This technology must not be abused to surveil, intimidate, or criminalize individuals engaging in lawful behavior,” Giannoulias said in a statement. “License plate readers can serve as important law enforcement tools, but safeguards are essential.”

Further compounding the issue, Giannoulias revealed that Mount Prospect police also engaged in immigration-related data searches—262 in total between mid-January and April—sharing license plate data with out-of-state agencies, another violation of the 2023 law. If confirmed, these actions could lead to Mount Prospect losing access to state funding, Deputy Secretary of State Scott Burnham stated.

The incident came to light after it was reported that the Texas sheriff issued a nationwide data request through Flock Safety, a private company managing over 83,000 license plate-reading cameras. In response, Giannoulias directed Flock Safety to block access to 62 out-of-state agencies suspected of misusing the data for abortion or immigration enforcement. Flock has since implemented a filter system to flag and reject data requests containing keywords such as “abortion” and “immigration.”

The ALPR technology, widely used by law enforcement across the country, captures thousands of images of license plates daily. While the system has proven effective in solving crimes such as carjackings, locating missing persons, and recovering stolen vehicles, it also raises serious privacy concerns. Legal experts warn that the data is vulnerable to misuse due to limited oversight and reliance on police departments self-reporting their intended use.

“We’re basically just asking cops to pinky-swear that they won’t misuse this data and then act shocked when they do,” said Albert Fox Cahn, executive director of the Surveillance Technology Oversight Project.

Illinois is among 22 states and the District of Columbia that have enacted “shield laws” to protect abortion seekers and providers from legal repercussions in anti-abortion states. The 2023 law limiting ALPR data use marked a first in the nation and reflected the state’s broader legislative response to the fall of Roe v. Wade.

As part of the compliance overhaul, Illinois law enforcement agencies will now be subjected to regular audits to detect unusual trends or spikes in data requests that may indicate misuse. The Secretary of State's Office is expected to roll out the audit program statewide in the coming weeks.