The incident occurred at about 2:05 a.m. last Friday in the 100-block of West Kinzie Street.
Police released surveillance images of a suspect who police said struck a male victim, leaving him unconscious. Police said the victim was transported to the hospital with serious injuries.
Police said the suspect is 5'9-5'11 tall, 150-170 pounds and had a black hooded sweatshirt, a black ball cap, black and white tank top, black shorts, white gym shoes and had an ankle monitoring device on his ankle.
Anyone with information is asked to contact Area 3 detectives at (312) 744-8261.
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