Shane Colombo, 25, was waiting at a bus stop in the Rogers Park neighborhood Sunday night when he was caught in the crossfire between two people, Chicago police said. He later died at Saint Francis Hospital in Evanston.
Colombo was a native of Sun City, California, who was due to start a psychology Ph.D. program at Northwestern University in the fall.
Police released photos of three suspects wanted in connection with Colombo's death on Wednesday.
On Friday, Colombo's family and community activist Andrew Holmes announced a $2,000 reward for anyone who can identify the men.
Anyone with information is asked to call 800-883-5587.