The shooting happened around 12:19 a.m. at 840 North Cambridge Avenue, between Chicago Avenue and Chestnut Street.
Citing preliminary reports, the shooter is a black male, about 5’6”, and 140 pounds.
The gunman was wearing a clear, plastic Halloween mask, a blue hooded sweatshirt, and black jeans.
Investigators identified the shooting victim as 36-year-old Obie Sanders, a black man from the South Side of Chicago.
It appears Sanders has a criminal history, according to police dispatch reports.
The 36-year-old shooting victim was taken to Northwestern Memorial Hospital in unknown condition.