(CNN) A black man says he was racially profiled by white police officers while he was being treated at an Illinois hospital and went for a walk hooked up to an IV drip.

Police arrested Shaquille Dukes, 24, of misdemeanor disorderly conduct after a security guard called them, saying that Dukes was trying to steal medical equipment.

The Freeport Police Department confirmed Sunday in a statement that Dukes filed a complaint "alleging unfair and biased conduct by responding officers." The department said it has retained an outside, third-party investigator to "gather the facts, interview all parties involved, and determine whether officers conducted themselves in adherence to department policies and guidelines."

Dukes wrote on Facebook that he was on vacation in Freeport, about 100 miles west of Chicago, when he came down with double pneumonia and went to the hospital. He told CNN he was admitted to FHN Memorial Hospital for two days.

On the morning of the second day, June 9, he said he was feeling better and asked doctors if he could go for a walk. He went outside with his boyfriend and his brother, still wearing his hospital gown and pushing a steroid and antibiotic IV drip.

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