Joining the City of Chicago and the Regional Transportation Authority (RTA), Cook County is suing the Illinois towns Kankakee and Channahon for millions in alleged lost revenue. Cook County Board President Toni Preckwinkle said Monday that the two cities have allowed Chicago companies to divert paperwork through the towns to avoid paying higher sales taxes.

“This type of practice in any municipality or government is fundamentally wrong, and we’re determined to protect interests of our Cook County government, and those businesses that are complying with the law,” said Preckwinkle.

The county also wants the names of the businesses allegedly diverting these funds; they haven’t been revealed because the city government claims that would violate contracts.

Though State’s Attoney Anita Alvarez said “this promises to be a complex piece of litigation,” Cook County is filing separately to better its odds that it will recoup money. Additionally, if Cook County piggybacked on the exisiting lawsuit, it would have to pay for the outside legal counsel retained by the City of Chicaog. “I have confidence that we have the ability in house, to be able to do this,” said Alvarez.

The county also hopes the lawsuit will reveal the names of the companies allegedly diverting the paperwork.

When asked if the lawsuit would drive businesses out of Chicago, and even potentially out of the state, Preckwinkle said, “I don’t believe so. I think they do business in Cook County because they find our workforce and our transportation and our infrastructure conducive to our businesses, and I don’t think that’s going to change if we make them comply with the law.”

The mayor of Kankakee has said the town is doing nothing illegal.