The stabbing happened in the Greater Grand Crossing neighborhood near East 75th Street and South Prairie Avenue, police said.
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Police said a 24-year-old man was arguing with someone inside a store at about 4:23 p.m. That person then pulled out a knife and stabbed him in the neck.
The victim was transported to the University of Chicago Medical Center in critical condition, police said. Another person, who suffered an unspecified minor injury, was taken to St. Bernard Hospital, Chicago fire officials said.
Area One detectives are investigating. Officials did not immediately provide further information about the incident.
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