On November 21, In 2023, field intelligence officers within the Department of Homeland Security quietly deleted Chicago Police Department records. It was not the usual clean.

For seven months, the data — which included requests from nearly 900,000 Chicagoland residents — has been on federal servers in violation of a deletion order issued by the intelligence watchdog. A subsequent inquiry found that nearly 800,000 files were kept, which a later report said violated rules designed to prevent domestic intelligence operations from targeting legal U.S. residents. The records began as private exchanges between DHS analysts and Chicago police, a test of how local intelligence can feed federal government watch lists. The idea was to see if street-level data could surface undocumented gang members in airport queues and at border crossings. The experiment collapsed amid what government reports describe as a chain of mismanagement and oversight failures.

Internal memos reviewed by Wired show that the dataset was first requested in the summer of 2021 by a field officer in DHS’s Office of Intelligence and Analysis (I&A). By this time, Chicago’s gang data was already notorious. It is riddled with contradictions and errors. City inspectors warned that police could not guarantee its accuracy. Entries created by the police included persons born before 1901 and others who were newborns. Some were labeled by police as gang members but not affiliated with any particular group.

The police listed people’s occupations as “scambags,” “turds,” or simply “blacks,” denigrating themselves in the statistics. Neither arrest nor conviction was necessary to make the list.

Prosecutors and police relied on the positions of alleged gang members in their filings and investigations. He shadowed defendants through bail hearings and sentencing. For immigrants, it carries extra weight. Chicago’s sanctuary rules banned most data sharing with immigration officers, but left a loophole for “unknown gang members” at the time. Over a decade, immigration officers tapped into the database more than 32,000 times.

The I & A memos—first obtained through a public records request at NYU’s Brennan Center for Justice—show that what began as a limited data-sharing experiment within DHS quickly became mired in a cascade of procedural errors. Chicagoland’s data request moved through layers of review with no clear owner, ignoring or bypassing its legal safeguards. By the time the data landed on I&A’s server around April 2022, the field officer who initiated the transfer had left his post. The experiment eventually fell under his own paperwork. Signatures are missed, audits are never filed, and deletion deadlines go unnoticed. The defenders’ goal of keeping intelligence work outward — on foreign threats, not Americans — was easily thwarted.

Faced with passing, I finally killed the project in November 2023, wiped the dataset and memorialized the breach in a formal report.

Spencer Reynolds, a senior attorney at the Brennan Center, says the incident illustrates how federal intelligence officers can override local sanctuary laws. “This is a function of the Intelligence Office’s so-called sanctity protections that prevent cities like Chicago from directly cooperating with Snow,” he says. “Federal intelligence officers can access the data, package it, and then hand it over to immigration enforcement, circumventing important policies to protect residents.”