The man is wanted for robbing Plato's Closet resale shop at Broadway and Diversey over the weekend as well as robbing a FedEx store near Fullerton and Halsted on January 9.
In both cases, the man entered, produced a small revolver, and demanded cash.
FedEx witnesses described the man as black, 45- to 50-years-old, wearing a red and gray plaid trapper style winter hat, a black jacket, partially faded blue jeans, and white gym shoes.
Surveillance footage of Saturday's robbery on Broadway show the man to be black, 40 to 45 years old, 5'10" tall, 150 pounds, wearing a tan trapper style hat, a black trench coat over a gray hoodie, blue jeans, and white gym shoes.
Detectives are asking anyone with information to contact them at 312.744.8263 and refer to Pattern P15-N-054(BA).