Authorities say 27-year-old Terence Cunningham got in an argument with the man inside the Middle Store Deli & Grocery on Woodfield Road in Lakeview on December 16.
He allegedly waited for him outside and shot the 32-year-old in the shoulder and chest when he left the building.
Investigators say he then tried to rob the victim before victim before running away.
Detectives arrested Cunningham around 11:30 p.m. Sunday.
He is charged with assault, criminal use of a firearm, attempted robbery and criminal possession of a weapon.
