Fred Tsao of the Illinois Coalition for Immigrant and Refugee Rights speaks during a Cook County Board of Commissioners Legislation and Intergovernmental Relations Committee hearing on Wednesday.

A decade-old firewall designed to prevent the U.S. Office of Immigrations and Customs Enforcement (ICE) from getting ahold of Cook County data hasn’t stopped the federal agency from trying anyway, and county officials are straining to reinforce confidence that some data won’t slip through the cracks.

In Fiscal Year 2020, ICE issued more than 1,000 detainer requests to Cook County, which Cook County law enforcement agencies rejected due to the county’s sanctuary policies. The Cook County Board of Commissioners’ Legislation and Intergovernmental Relations Committee met for a hearing Wednesday to investigate whether ICE is bypassing the county’s sanctuary protections through the use of data brokers.