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CHICAGO — Federal agents raided a popular pizza restaurant in Chicago Wednesday.

Law enforcement were inside Parlor Pizza locations in Wicker Park, River North and the West Loop. Police and federal agents are working with the Illinois Department of Revenue on an unspecified criminal investigation.

Witnesses said they also saw employees with the Chicago Building Department taking pictures inside the restaurant.

The city posted orange closure signs on the entrance doors, but it’s unclear how long the businesses will be closed to customers.

Employees who showed up to work at the locations were told to go home.

In a statement, the Illinois Department of Revenue said:

In the event of potential violations of the Illinois Tax Act and related offenses, our bureau of criminal investigations will investigate potential violations. The Illinois Department of Revenue cannot comment on ongoing investigations, however, or their existence.

An attorney declined to comment.

WGN News reached out to the restaurant owner for comment but did not hear back.