The shooting happened at the busy North Center intersection of North Lincoln and West Berteau avenues just after 9 a.m. on Monday.
The retired sergeant, a 74-year-old man, was getting out of his Jeep Cherokee when two people opened fire, striking him at least three times, police said.
The victim, who lives nearby, was taken in critical condition to the hospital for surgery.
CPD's SWAT team was brought in to search for the two suspects.
About two hours after the shooting, exclusive video shows one man, who police say is a person of interest, being escorted out of a Lincoln Avenue store front and taken into custody just a few feet from where the retired sergeant was shot.
On Wednesday, Chicago police said the person of interest was released without charges.
What motivated the shooting is still unknown.
Alderman Matt Martin said the sergeant's condition is improving.
READ ALSO | Retired Chicago police sergeant shot at least 3 times, critically injured in North Center: officials
It is unclear if the man shown in the video is the person of interest that police released.
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