The person behind the hate-filled tirades reportedly tried to make it look like the letter was coming from the courts.
The letter is titled "Court Order" with a return address of the Skokie Courthouse and a return stamp from Carol Stream.
It is filled with racial slurs and tells the establishment to shut down or face gang activity. The documents are also signed with the name of a judge from the Skokie Courthouse, police said.
The letters were sent to an Afghani restaurant, a Mexican cafe and an Indian-Nepalese restaurant in Evanston's business district.
Ovo Frito Cafe is a gathering place where the owners try to make customers feel comfortable, as if they are at home. But someone went out of the way to make them feel frightened.
Zinnia Iglesias owns Ovo Frito Café along with her husband, Roberto Flores. She said she received one of the hate-filed letters on Monday and that it appeared to come from the Cook County Courthouse in Skokie, telling her to close the restaurant.
"It looked like a court order. I was surprised. I read it and it was a hate letter, demanding us to close down," Iglesias said. "I called a friend and we took the letter to the police and filed a report."
The letter is easy to spot as fake but the discomfort caused is real. Residents say they won't stand for it.
"They work so hard to provide an amazing thing for our community, to feed and take care of us and to be treated like that is not right." said Patrick Hughes, a customer and friend of Iglesias and Flores.
Judge Timothy Evans, chief judge of the Cook County Courts, said he has been alerted about the letters.
"I’m indignant over this blatant attack on the judiciary," Judge Evans said. "By falsely attributing abusive and racist comments to Circuit Court of Cook County judges, it impugns their hard work and integrity and may create a dangerous situation."
Evanston police are investigating along with the Cook County Sheriff's Police Department and the United States Postal Inspection Service.
The FBI and the U.S. Attorney's office have also been notified.