Surveillance images show the man carrying a shopping bag out of the Round One Entertainment Center at the Fox Valley Mall.
Police said the bag was filled with items a little girl bought using her birthday money.
Anyone who recognizes him is asked to contact Aurora detectives at 630-256-5500 or the Aurora Area Crimestoppers tip line at 630-892-1000. Callers could be eligible for a reward of up to $5,000.