Police say he then committed an act of indecent exposure before fleeing on a tan bicycle.
The man is described as a 24- or 25-year-old black man, about 6 feet tall and weighing 155 to 165 pounds.
He has brown eyes, black hair and a tattoo on his left ring finger.
He was last seen wearing a tan blazer, white t-shirt and blue jeans.
Anyone with information is urged to call Area One detectives at (312) 747 8380.