Friends say he was trying to hail a cab after he helped a friend get home. A witness told police she heard gunshots then saw two men walking from the scene.
Mueller was part owner of Nonna's Italian Pizzaria at 1543 N. Sedgwick. He's being remembered as a hard worker and dedicated friend.
"Ne was one of the nicest guys. You could see it right from his smile. Every time he was around, he just made you feel good. He's that type of person. You could be hanging out with just having the best time," said friend Walter Oestmann.
Police are looking into a motive for the shooting.